Comparison of readout systems for high-rate silicon photomultiplier applications
M. L. Wong, M. Kołodziej, K. Briggl, R. Hetzel, G. Korcyl, R. Lalik, A. Malige, A. Magiera, G. Ostrzołek, K. Rusiecka, A. Stahl, V. Urbanevych, M. Wiebusch, A. Wrońska
abstract
Recent years have shown an increased use of silicon photomultipliers (SiPM) in experimentsas they are of reasonable cost, have relatively low power consumption and are easily available in avariety of form factors allowing for a large number of readout channels. At the same time, experimentsare generating data at increasingly high rates requiring the use of more efficient readout systems. Inthis work, the dead time, efficiency, dynamic range, coincidence time resolution and energy resolutionof five different readout systems at various stages of maturity are evaluated to determine the bestsystem for acquiring data from a detector in a high rate experiment. Additional functionalities ofthe systems are also discussed.
Near-field coded-mask technique and its potential for proton therapy monitoring
R. Hetzel, V. Urbanevych, A. Bolke, J. Kasper, M. Kercz, M. Kołodziej, A. Magiera, F. Mueller, S. Müller, M. Rafecas, K. Rusiecka, D. Schug, V. Schulz, A. Stahl, B. Weissler, M.-L. Wong, A. Wrońska
abstract
Objective. Prompt-gamma imaging encompasses several approaches to the online monitoring of the beam range or deposited dose distribution in proton therapy. We test one of the imaging techniques - a coded mask approach - both experimentally and via simulations. Approach. Two imaging setups have been investigated experimentally. Each of them comprised a structured tungsten collimator in the form of a modified uniformly redundant array mask and a LYSO:Ce scintillation detector of fine granularity. The setups differed in detector dimensions and operation mode (1D or 2D imaging). A series of measurements with radioactive sources have been conducted, testing the performance of the setups for near-field gamma imaging. Additionally, Monte Carlo simulations of a larger setup of the same type were conducted, investigating its performance with a realistic gamma source distribution occurring during proton therapy. Main results. The images of point-like sources reconstructed from two small-scale prototypes' data using the maximum-likelihood expectation maximisation algorithm constitute the experimental proof of principle for the near-field coded-mask imaging modality, both in the 1D and the 2D mode. Their precision allowed us to calibrate out certain systematic offsets appearing due to the limited alignment accuracy of setup elements. The simulation of the full-scale setup yielded a mean distal falloff retrieval precision of 0.72 mm in the studies for beam energy range 89.5?107.9 MeV and with 1 × 108 protons (a typical number for distal spots). The implemented algorithm of image reconstruction is relatively fast?a typical procedure needs several seconds. Significance. Coded-mask imaging appears a valid option for proton therapy monitoring. The results of simulations let us conclude that the proposed full-scale setup is competitive with the knife-edge-shaped and the multi-parallel slit cameras investigated by other groups.
First search for axionlike particles in a storage ring using a polarized deuteron beam
S. Karanth, E.J. Stephenson, S.P. Chang, V. Hejny, S. Park, J. Pretz, Y.K. Semertzidis, A. Wirzba, A. Wrońska, F. Abusaif, A. Aggarwal, A. Aksentev, B. Alberdi, A. Andres, L. Barion, I. Bekman, M. Beyß, C. Böhme, B. Breitkreutz, C. von Byern, N. Canale, G. Ciullo, S. Dymov, N.-O. Fröhlich, R. Gebel, K. Grigoryev, D. Grzonka, J. Hetzel, O. Javakhishvili, H. Jeong, A. Kacharava, V. Kamerdzhiev, I. Keshelashvili, A. Kononov, K. Laihem, A. Lehrach, P. Lenisa, N. Lomidze, B. Lorentz, A. Magiera, D. Mchedlishvili, F. Müller, A. Nass, N.N. Nikolaev, A. Pesce, V. Poncza, D. Prasuhn, F. Rathmann, A. Saleev, D. Shergelashvili, V. Shmakova, N. Shurkhno, S. Siddique, J. Slim, H. Soltner, R. Stassen, H. Ströher, M. Tabidze, G. Tagliente, Y. Valdau, M. Vitz, T. Wagner, P. Wüstner
abstract
Based on the notion that the local dark-matter field of axions or axionlike particles (ALPs) in our Galaxy induces oscillating couplings to the spins of nucleons and nuclei (via the electric dipole moment of the latter and/or the paramagnetic axion-wind effect), we establish the feasibility of a new method to search for ALPs in storage rings. Based on previous work that allows us to maintain the in-plane polarization of a stored deuteron beam for a few hundred seconds, we perform a first proof-of-principle experiment at the Cooler Synchrotron (COSY) to scan momenta near 970??MeV/c. This entails a scan of the spin-precession frequency. At resonance between the spin-precession frequency of deuterons and the ALP-induced electric dipole moment (EDM) oscillation frequency, there is an accumulation of the polarization component out of the ring plane. Since the axion frequency is unknown, the momentum of the beam and, consequently, the spin-precession frequency are ramped to search for a vertical polarization change that occurs when the resonance is crossed. At COSY, four beam bunches with different polarization directions are used to make sure that no resonance is missed because of the unknown relative phase between the polarization precession and the axion or ALP field. A frequency window of 1.5 kHz width around the spin-precession frequency of 121 kHz is scanned. We describe the experimental procedure and a test of the methodology with the help of a radio-frequency Wien filter located on the COSY ring. No ALP resonance is observed. As a consequence, an upper limit of the oscillating EDM component of the deuteron as well as its axion coupling constants are provided.
A systematic study of LYSO:Ce, LuAG:Ce and GAGG:Ce scintillating fibers properties
K. Rusiecka, R. Hetzel, J. Kasper, M. Kazemi Kozani, N. Kohlhase, M. Kołodziej R. Lalik, A. Magiera, W. Migdał, M. Rafecas, A. Stahl, V. Urbanevyvh, M. L. Wong, A. Wrońska
abstract
Study of 99Mo and long-lived impurities produced through (p, x) reactions in the natMo
Arshiya Anees Ahmed, Aleksandra Wrońska, Andrzej Magiera, Ryszard Misiak, Mirosław Bartyzel, Jerzy W. Mietelski, Bogdan Wa?s
abstract
Using the stack-foil activation technique, excitation functions were measured for (p, x) reactions on target. The target was irradiated with a proton beam of 17 MeV kinetic energy. Along with the medically important radioisotopes / we studied other long-lived radio-impurities produced in the target. Cross sections of all the produced radioisotopes from reactions are compared with the available literature data, which show good agreement.
Three-body breakup in deuteron-deuteron collisions at 160 MeV including quasifree scattering
I. Ciepal, G. Khatri, K. Bodek, A. Deltuva, N. Kalantar-Nayestanaki, S. Kistryn, B. Klos, A. Kozela, J. Kubos, P. Kulessa, A. Lobejko, A. Magiera, J. Messchendorp, I. Mazumdar, W. Parol, R. Ramazani-Sharifabadi, D. Rozpedzik, I. Skwira-Chalot, E. Stephan, A. Wilczek, B. Wloch, A. Wronska, J. Zejma
abstract
A set of differential cross section of the three-body H-2(d, dp)n breakup reaction at 160-MeV deuteron beam energy is presented for 147 configurations covering a wide kinematical region around quasifree scattering. The experiment was performed at KVI in Groningen, the Netherlands, using the BINA detector. The cross-section data have been normalized to the H-2(d, d)H-2 elastic-scattering cross section. The data are compared to the results of recent single-scattering approximation (SSA) calculations for three-cluster breakup in deuteron-deuteron collisions. This comparison shows that SSA provides the correct order of magnitude of the cross sections. The studied energy is probably too low to meet the SSA assumptions which prevents better accuracy of the description.
Studies of Deuteron Breakup Reactions in Deuteron-Deuteron Collisions at 160MeV with BINA
I. Ciepal, K. Bodek, N. Kalantar-Nayestanaki, G. Khatri, S. Kistryn, B. Klos, A. Kozela, J. Kubos, P. Kulessa, A. Lobejko, A. Magiera, I. Mazumdar, J. Messchendorp, W. Parol, D. Rozpedzik, I. Skwira-Chalot, E. Stephan, A. Wilczek, B. Wloch, A. Wronska, J. Zejma
abstract
A rich set of differential cross section of the three-body 2H(d,dp)n breakup reaction at 160MeV deuteron beam energy has been measured over a large range of the available phase space. The experiment was performed at KVI in Groningen, the Netherlands, using the BINA detector. The cross-section data for the breakup reaction have been normalized to the simultaneously measured 2H(d,d)2H elastic scattering cross section. The breakup cross sections obtained for 147 kinematically complete configurations near the quasi-free scattering kinematics are compared to the recent approximate calculations for the three-cluster breakup in deuteron-deuteron collisions. The cross sections for 294 kinematic configurations of the quasi-free scattering regime, for which no theoretical calculations exist, are also presented. Besides the three-body breakup, semi-inclusive energy distributions for the four-body 2H(d,pp)nn breakup are reported.
Investigation of the cross section for dd elastic scattering and dd -> n He-3 reactions at 160 MeV
I. Ciepal, J. Kubos, K. Bodek, N. Kalantar-Nayestanaki, G. Khatri, S. Kistryn, B. Klos, A. Kozela, P. Kulessa, A. Lobejko, A. Magiera, J. Messchendorp, I. Mazumdar, W. Parol, D. Rozpedzik, I. Skwira-Chalot, E. Stephan, A. Wilczek, B. Wloch, A. Wronska, J. Zejma
abstract
Differential cross sections of H-2(d, d)H-2 elastic scattering and proton transfer H-2(d,He-3)n reactions at 160 MeV beam energy have been obtained. They have been normalized relative to the existing cross-section data for the H-2(d, d)H-2 elastic scattering at 180 and 130 MeV, benefitting from the negligible energy dependence of this observable at certain range of the four-momentum transfer. The experiment was performed at KVI in Groningen, the Netherlands, using the BINA detector. The elastic scattering data are compared to theoretical predictions based on the lowest-order term in the Neumann series expansion for four-nucleon transition operators. The calculations underpredict the data. The data presented in this paper can be used to validate the future theoretical findings.
Search for C violation in the decay eta -> pi(0)e(+)e(-) with WASA-at-COSY
R. Adlarson, WAC. Collaboration, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, A. Bondar, M. Buescher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, R. Fedorets, K. Foehl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Huesken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, A. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, R. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, R. Marciniewski, B. Marianski, HP. Morsch, R. Moskal, H. Ohm, W. Parol, EP. Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, et al.
abstract
We report on the search for the rare decay eta -> pi(0)e(+)e(-) which is of interest to study C violation in the electromagnetic interaction which would indicate contributions from physics beyond the Standard Model, since the allowed decay via a two-photon intermediate state is strongly suppressed. The experiment has been performed using the WASA-at-COSY installation, located at the COSY accelerator of the Forschungszentrum Julich, Germany. In total 3 x 10(7) events of the reaction pd -> He-3 eta have been recorded at an excess energy of Q = 59.8MeV. Based on this data set the C parity violating decay eta -> pi(0)gamma* -> pi(0)e(+)e(-) via a single-photon intermediate state has been searched for, resulting in new upper limits of Gamma(eta -> pi(0)e(+) e(-))/Gamma(eta -> pi(+) pi(-) pi(0)) < 3.28 x 10(-5) and Gamma(eta -> pi(0)e(+) e(-))/Gamma(eta -> all)< 7.5 x 10(-6) (CL=90%), respectively. (c) 2018 The Author. Published by Elsevier B.V.
SHAPE OF THE SPECTRAL LINE AND GAMMA ANGULAR DISTRIBUTION OF THE C-12(p,p 'gamma(4.44))C-12 REACTION
K. Rusiecka, A. Wronska, A. Magiera, GGG. Obrzud, L. Kelleter, K. Laihem, J. Leidner, A. Stahl, A. Chrobak, A. Konefal
abstract
A model explaining the shape of the spectral line in the C-12(p,p'gamma(4.44))C-12 nuclear reaction has been applied to data collected during an experiment conducted at the Heidelberg Ion-Beam Therapy Center. Spectra were recorded for a graphite target setup, initial proton beam energies of 70.54 MeV and 88.97 MeV, which were later degraded before reaching the main target, and detection angles ranging from 90 degrees to 150 degrees. The model calculations reproduced experimental data and determined the angular distribution of the nuclear reaction. This article presents the details of the model along with a description of the subsequent analysis steps and results.
Isotensor Dibaryon in the pp -> pp pi(+)pi(-) Reaction?
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, W. Parol, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, V. Serdyuk, B. Shwartz, T. Skorodko, M. Skurzok, J. Smyrski, et al.
abstract
Exclusive measurements of the quasifree pp -> pp pi(+)pi(-) reaction have been carried out at WASA@ COSY by means of pd collisions at T-p = 1.2 GeV. Total and differential cross sections have been extracted covering the energy region T-p = 1.08-1.36 GeV, which is the region of N* (1440) and Delta(123)Delta(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor Delta N dibaryon resonance with I(J(P)) = 2(1(+)) produced associatedly with a pion is able to overcome these deficiencies.
Total and differential cross sections of eta-production in proton-deuteron fusion for excess energies between Q(eta)=13 MeV and Q(eta)=81 MeV
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erveno, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, A. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, W. Parol, EP. del Rio, NM. Piskunovu, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
New data on both total and differential cross sections of the production of eta mesons in proton-deuteron fusion to He-3 eta in the excess energy region 13.6 MeV <= Q(eta) <= 80.9 MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Julich, using a proton beam at 15 different beam momenta between p(p) = 1.60 GeV/c and p(p) = 1.74 GeV/c. While significant structure of the total cross section is observed in the energy region 20 MeV less than or similar to Q(eta) less than or similar to 60 MeV, a previously reported sharp variation around Q(eta) approximate to 50 MeV cannot be confirmed. Angular distributions show the typical forward- peaking that was noted earlier. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a wide interval. (c) 2018 The Author. Published by Elsevier B.V.
Importance of d-wave contributions in the charge symmetry breaking reaction dd -> He-4 pi0
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, C. Hanhart, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, W. Parol, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
This letter reports a first quantitative analysis of the contribution of higher partial waves in the charge symmetry breaking reaction dd -> He-4 pi(0) using the WASA-at-COSY detector setup at an excess energy of Q = 60 MeV. The determined differential cross section can be parametrized as d sigma/d Omega = a + b cos(2) theta*, where theta* is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are a = (1.55 +/- 0.46(stat)(-0.8)(+0.32)(syst)) pb/sr and b = (13.1 +/- 2.1(stat)(-2.7)(+1.0)(syst)) pb/sr. The data are compatible with vanishing p-waves and a sizable d-wave contribution. This finding should strongly constrain the contribution of the A isobar to the dd -> He-4 pi(0) reaction and is, therefore, crucial for a quantitative understanding of quark mass effects in nuclear production reactions. (C) 2018 The Author(s). Published by Elsevier B.V.
Radon Rn-222 in drinking water of West Pomeranian Voivodeship and Kuyavian-Pomeranian Voivodeship, Poland
K. Wieprzowski, M. Bekas, E. Wasniewska, A. Wardzinski, A. Magiera
abstract
Radon Rn-222 is a commonly occurring natural radionuclide found in the environment from uranium-radium radioactive series, which is the decay product of radium Ra-226. The presence of radon carries negative health effects. It is, in fact, classified as a carcinogen, and therefore, it is necessary to continuously monitor its concentration. The aim of this study was to determine the level of radon-222 concentration in water intended for human consumption in the two voivodeships of Poland: West Pomeranian and Kuyavian-Pomeranian. Measurements were performed for more than 60 intakes. The level of radon was measured by using the liquid scintillation counting method. The range of measured radon concentration in the water from the West Pomeranian Voivodeship was from 0.90 to 11.41 Bq/dm(3) with an average of 5.01 Bq/dm(3), while that from the Kuyavian-Pomeranian Voivodeship was from 1.22 to 24.20 Bq/dm(3) with an average of 4.67 Bq/dm(3). Only in three water intakes, the concentration of radon-222 exceeded the value of 10 Bq/dm(3). The obtained results allowed to conclude that population exposure associated with radon-222 in water is negligible and there is no need to take further action. In the case of three intakes where a higher concentration of radon was found, the potential exposure was low.
Phase measurement for driven spin oscillations in a storage ring
N. Hempelmann, V. Hejny, J. Pretz, H. Soltner, W. Augustyniak, Z. Bagdasarian, M. Bai, L. Barion, M. Berz, S. Chekmenev, G. Ciullo, S. Dymov, D. Eversmann, M. Gaisser, R. Gebel, K. Grigoryev, D. Grzonka, G. Guidoboni, D. Heberling, J. Hetzel, F. Hinder, A. Kacharava, V. Kamerdzhiev, I. Keshelashvili, I. Koop, A. Kulikov, A. Lehrach, P. Lenisa, N. Lomidze, B. Lorentz, P. Maanen, G. Macharashvili, A. Magiera, D. Mchedlishvili, S. Mey, F. Muller, A. Nass, NN. Nikolaev, M. Nioradze, A. Pesce, D. Prasuhn, F. Rathmann, M. Rosenthal, A. Saleev, V. Schmidt, Y. Semertzidis, Y. Senichev, V. Shmakova, A. Silenko, J. Slim, A. Stahl, R. Stassen, E. Stephenson, H. Stockhorst, H. Stroher, M. Tabidze, G. Tagliente, R. Talman, PT. Engblom, F. Trinkel, Y. Uzikov, Y. Valdau, E. Valetov, A. Vassiliev, C. Weidemann, A. Wronska, P. Wustner, et al.
abstract
This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in Julich using a vector polarized, bunched 0.97 GeV/c deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles.
Effect of electron beam cooling on transversal and longitudinal emittance of an external proton beam
K. Kilian, H. Machner, A. Magiera, D. Prasuhn, P. von Rossen, R. Siudak, HJ. Stein, H. Stockhorst
abstract
Benefits of electron cooling to the quality of extracted ion beams from storage rings are discussed. The transversal emittances of an external proton beam with and without electron cooling at injection energy are measured with the GEM detector assembly. While the horizontal emittance remains the vertical emittance shrinks by the cooling process. The longitudinal momentum variance is also reduced by cooling. (c) 2017 Elsevier B.V. All rights reserved.
Spin Dependence of eta Meson Production in Proton-Proton Collisions Close to Threshold
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, SD. Bass, FS. Bergmann, M. Berlowski, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, W. Parol, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high polarization degree of the proton beam of COSY, the reaction (p) over right arrowp -> pp eta has been measured close to threshold to explore the analyzing power A(y). The angular distribution of A(y) is determined with the precision improved by more than 1 order of magnitude with respect to previous results, allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q = 15 MeV, signaling s-wave production with no evidence for higher partial waves. At Q = 72 MeV the data reveal strong interference of Ps and Pp partial waves and cancellation of (Pp)(2) and Ss*Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the eta meson.
Long-term effects of premature birth on somatic development in women through adolescence and adulthood
K. Kaczmarczyk, A. Pituch-Zdanowska, I. Wiszomirska, A. Magiera, A. Ronikier
abstract
Objectives To evaluate the long-term consequences of preterm birth on anthropometric parameters in women in adolescence and into adulthood. Methods Seventy girls born preterm (age 12.221.52 years) and 48 born at term participated in the first stage. Eighteen years later, 13 of the same women participated in a follow-up and were compared with a control group of 27 women. We compared anthropometric results across the two examinations, and in the second stage, also assessed body composition using bioelectrical impedance analysis. Results No significant differences were found in anthropometric parameters or the content of individual components of the body between the preterm-born and control groups. However, the preterm-born group showed a tendency for higher average fat mass and lower fat-free and soft lean mass compared with the control group, and had a significantly higher mean waist-hip ratio. Conclusions Preterm birth does not adversely affect somatic development in girls during adolescence, but shows a correlation with an elevated waist-hip ratio in adulthood.
Non-equilibrium processes in p + Ag collisions at GeV energies
M. Fidelus,.., B. Kamys, S. Kistryn, A. Magiera, Z. Rudy, S. Sharma et al.,
abstract
The double differential spectra d2?/d?dE of p, d, t, He3,4,6, Li6,7,8,9, Be7,9,10, and B10,11,12 were measured at seven scattering angles, 15.6?, 20?, 35?, 50?, 65?, 80?, and 100?, in the laboratory system for proton induced reactions on a silver target. Measurements were done for three proton energies: 1.2, 1.9, and 2.5 GeV. The experimental data were compared to calculations performed by means of two-step theoretical microscopic models. The first step of the reaction was described by the intranuclear cascade model incl4.6 and the second one by four different models (ABLA07, GEM2, gemini++, and SMM) using their standard parameter settings. Systematic deviations of the data from predictions of the models were observed. The deviations were especially large for the forward scattering angles and for the kinetic energy of emitted particles in the range from about 50 to 150 MeV. This suggests that some important non-equilibrium mechanism is lacking in the present day microscopic models of proton-nucleus collisions in the studied beam energy range.
Non-equilibrium processes in p plus Ag collisions at GeV energies
M. Fidelus, D. Filges, F. Goldenbaum, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, SK. Sharma, R. Siudak, M. Wojciechowski
abstract
The double differential spectra d(2)sigma/d Omega dE of p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11,B-12 were measured at seven scattering angles, 15.6 degrees, 20 degrees, 35 degrees, 50 degrees, 65 degrees, 80 degrees, and 100 degrees, in the laboratory system for proton induced reactions on a silver target. Measurements were done for three proton energies: 1.2, 1.9, and 2.5 GeV. The experimental data were compared to calculations performed by means of two-step theoretical microscopic models. The first step of the reaction was described by the intranuclear cascade model INCL4.6 and the second one by four different models (ABLA07, GEM2, GEMINI++, and SMM) using their standard parameter settings. Systematic deviations of the data from predictions of the models were observed. The deviations were especially large for the forward scattering angles and for the kinetic energy of emitted particles in the range from about 50 to 150 MeV. This suggests that some important non-equilibrium mechanism is lacking in the present day microscopic models of proton-nucleus collisions in the studied beam energy range.
Isoscalar single-pion production in the region of Roper and d*(2380) resonances
P. Adlarsona, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, W. Parol, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Exclusive measurements of the quasi-free pn -> pp pi(-) and pp -> pp pi(0) reactions have been performed by means of pd collisions at T-p= 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region T-p= 0.95-1.3 GeV (root s = 2.3-2.46 GeV), which includes the regions of triangle(1232), N*(1440) and d*(2380) resonance excitations. From these measurements the isoscalar single-pion production has been extracted, for which data existed so far only below T-p = 1 GeV. We observe a substantial increase of this cross section around 1 GeV, which can be related to the Roper resonance N*(1440), the strength of which shows up isolated from the triangle resonance in the isoscalar (N pi)(I=0) invariant-mass spectrum. No evidence for a decay of the dibaryon resonance d*(2380) into the isoscalar (NN pi)(I=0) channel is found. An upper limit of 180 mu b (90% CL.) corresponding to a branching ratio of 9% has been deduced. (c) 2017 The Author(s). Published by Elsevier B.V.
EXPERIMENTAL VERIFICATION OF KEY CROSS SECTIONS FOR PROMPT-GAMMA IMAGING IN PROTON THERAPY
A. Wronska, AA. Ahmed, A. Andres, P. Bednarczyk, J. Besuglow, G. Gazdowicz, K. Herweg, R. Hetzel, J. Kasper, L. Kelleter, A. Konefal, P. Kulessa, K. Laihem, J. Leidner, A. Magiera, K. Rusiecka, D. Stachura, A. Stahl, M. Zieblinski
abstract
We present experimental investigation of cross sections for processes crucial in view of prompt-gamma imaging. The prompt-gamma rays were produced from an interaction of a proton beam with different phantom materials composed of carbon, oxygen and hydrogen. The used target setup allowed precise selection of the investigated depth in the phantom. We studied details of the dependence of prompt-gamma yields on beam energy, detection angle and elemental composition of irradiated phantom. The analysis was focused on the discrete transitions with the largest cross sections: 4.44 MeV in C-12 and 6.13 MeV in O-16. The results are presented in form of profiles of the prompt-gamma yield as a function of depth. They are compared to calculations including different cross-section models. Obtained results are in agreement with the model exploiting cross-section data collected from the literature, but the comparison with the TALYS model shows discrepancies. In the latest experiment, special attention was paid to the shape of the distal fall-off. The width of that fall-off is directly linked to the resolution of prompt-gamma based methods of range verification. Preliminary results on the beam-energy dependence of this quantity are presented.
Control of systematic uncertainties in the storage ring search for an electric dipole moment by measuring the electric quadrupole moment
A. Magiera
abstract
Measurements of electric dipole moment (EDM) for light hadrons with use of a storage ring have been proposed. The expected effect is very small, therefore various subtle effects need to be considered. In particular, interaction of particle's magnetic dipole moment and electric quadrupole moment with electromagnetic field gradients can produce an effect of a similar order of magnitude as that expected for EDM. This paper describes a very promising method employing an rf Wien filter, allowing to disentangle that contribution from the genuine EDM effect. It is shown that both these effects could be separated by the proper setting of the rf Wien filter frequency and phase. In the EDM measurement the magnitude of systematic uncertainties plays a key role and they should be under strict control. It is shown that particles' interaction with field gradients offers also the possibility to estimate global systematic uncertainties with the precision necessary for an EDM measurement with the planned accuracy.
Measurement of the omega -> pi(+)pi(-)pi(0) Dalitz plot distribution The WASA-at-COSY Collaboration
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. RudyC, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Using the production reactions pd -> He-3 omega and pp -> pp omega, the Dalitz plot distribution for the omega -> pi(+)pi(-)pi(0)decay is studied with the WASA detector at COSY, based on a combined data sample of (4.408 +/- 0.042) x 10(4) events. The Dalitz plot density is parametrised by a product of the P-wave phase space and a polynomial expansion in the normalised polar Dalitz plot variables Z and phi. For the first time, a deviation from pure P-wave phase space is observed with a significance of 4.1 sigma. The deviation is parametrised by a linear term 1+2 alpha Z, with alpha determined to be +0.147 +/- 0.036, consistent with the expectations of rho-meson-type final-state interactions of the P-wave pion pairs. (C) 2017 The Author. Published by Elsevier B.V.
Spin tune mapping as a novel tool to probe the spin dynamics in storage rings
A. Saleev, NN. Nikolaev, F. Rathmann, W. Augustyniak, Z. Bagdasarian, M. Bai, L. Barion, M. Berz, S. Chekmenev, G. Ciullo, S. Dymov, D. Eversmann, M. Gaisser, R. Gebel, K. Grigoryev, D. Grzonka, G. Guidoboni, D. Heberling, V. Hejny, N. Hempelmann, J. Hetzel, F. Hinder, A. Kacharava, V. Kamerdzhiev, I. Keshelashvili, I. Koop, A. Kulikov, A. Lehrach, P. Lenisa, N. Lomidze, B. Lorentz, P. Maanen, G. Macharashvili, A. Magiera, D. Mchedlishvili, S. Mey, F. Muller, A. Nass, A. Pesce, D. Prasuhn, J. Pretz, M. Rosenthal, V. Schmidt, Y. Semertzidis, Y. Senichev, V. Shmakova, A. Silenko, J. Slim, H. Soltner, A. Stahl, R. Stassen, E. Stephenson, H. Stockhorst, H. Stroher, M. Tabidze, G. Tagliente, R. Talman, PT. Engblom, F. Trinkel, Y. Uzikov, Y. Valdau, E. Valetov, A. Vassiliev, C. Weidemann, A. Wronska, P. Wustner, P. Zupranski, et al.
abstract
Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called spin tune mapping, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 using polarized deuterons stored in the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than 2.8 mu rad.
Phase Locking the Spin Precession in a Storage Ring
N. Hempelmann, V. Hejny, J. Pretz, E. Stephenson, W. Augustyniak, Z. Bagdasarian, M. Bai, L. Barion, M. Berz, S. Chekmenev, G. Ciullo, S. Dymov, FJ. Etzkorn, D. Eversmann, M. Gaisser, R. Gebel, K. Grigoryev, D. Grzonka, G. Guidoboni, T. Hanraths, D. Heberling, J. Hetzel, F. Hinder, A. Kacharava, V. Kamerdzhiev, I. Keshelashvili, I. Koop, A. Kulikov, A. Lehrach, P. Lenisa, N. Lomidze, B. Lorentz, P. Maanen, G. Macharashvili, A. Magiera, D. Mchedlishvili, S. Mey, F. Muller, A. Nass, NN. Nikolaev, A. Pesce, D. Prasuhn, F. Rathmann, M. Rosenthal, A. Saleev, V. Schmidt, Y. Semertzidis, V. Shmakova, A. Silenko, J. Slim, H. Soltner, A. Stahl, R. Stassen, H. Stockhorst, H. Stroher, M. Tabidze, G. Tagliente, R. Talman, PT. Engblom, F. Trinkel, Y. Uzikov, Y. Valdau, E. Valetov, A. Vassiliev, C. Weidemann, A. Wronska, P. Wustner, et al.
abstract
This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/c bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate (approximate to 121 kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of sigma = 0.21 rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.
PROBING THREE-AND FOUR-NUCLEON INTERACTIONS WITH THE DEUTERON BREAKUP REACTION
I. Ciepal, I. Skwira-Chalot, S. Kistryn, A. Kozela, A. Magiera, E. Stephan
abstract
Research in the domain of few-nucleon systems concerns reactions involving a small number of nucleons in which observables can be compared directly to exact computational methods - rigorous solutions of the Fad-deev equations. The investigations of such systems reveal existence of various dynamical ingredients such as the three-nucleon force, the Coulomb force or relativistic effects. A large set of the cross-section data of the H-1 (d, pp)n breakup reaction obtained at energy of 130 MeV was used to trace the Coulomb force effects. Comparisons of the cross-section data with the predictions using the realistic Argonne 18 potential are presented. The new set of invariants was introduced to describe the process with three nucleons in the final state.
COMPARISON OF VARIOUS MODELS OF MONTE CARLO GEANT 4 CODE IN SIMULATIONS OF PROMPT GAMMA PRODUCTION
A. Chrobak, A. Konefal, A. Wronska, A. Magiera, K. Rusiecka, K. Laihem, D. Bockenhoff, S. Feyen
abstract
In this paper, results of simulations of the gamma-ray production in reactions with 70 MeV protons in a target of PMMA are presented. The data obtained by means of two versions of Geant 4 software, 9.3 and 10.01, have shown significant differences in the gamma-ray spectra. The comparison between the calculated spectra and the measured ones has been carried out. The tested versions do not give satisfactory agreement with the experimental result. The reason of the performed verification was the planned application of this simulation toolkit for the preparation of in vivo dosimetry based on the prompt gamma-ray measurements for the proton therapy.
Experimental Study of Three-Nucleon Dynamics in the Dp Breakup Collisions Using the WASA Detector
B. Klos, I. Ciepal, B. Jamroz, G. Khatri, S. Kistryn, A. Kozela, A. Magiera, W. Parol, I. Skwira-Chalot, E. Stephan
abstract
Until recently, all calculations of breakup observables were carried out in a non-relativistic regime. The relativistic treatment of the breakup reaction in 3N system is quite a new achievement. The detailed study of various aspects of few-nucleon system dynamics in medium energy region, with a particular emphasis on investigation of relativistic effects and their interplay with three nucleon force (3NF) becomes feasible with increasing available energy in the three nucleon system. Therefore an experiment to investigate the H-1(d, pp)n breakup cross section using a deuteron beam of 300, 340, 380 and 400 MeV and the WASA detector has been performed at COSY-Julich. The almost 4 pi geometry of the WASA detector gives an unique possibility to study variety of kinematic configurations, which reveal different sensitivity to aspects of dynamics of the three nucleon system. The main steps of the analysis, including energy calibration, PID, normalization and efficiency studies, and their impact on the final accuracy of the result, are discussed.
Search for eta-mesic He-4 in the dd -> (3)Hen pi(0) and dd -> (3)Hep pi(-) reactions with the WASA-at-COSY facility
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, E. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, NG. Kelkar, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magierae, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
The search for He-4-eta bound states was performed with the WASA-at-COSY facility via the measurement of the excitation function for the dd -> (3)Hen pi(0) and dd -> (3)Hep pi(-) processes. The deuteron beam momentum was varied continuously between 2.127 GeV/c and 2.422 GeV/c, corresponding to the excess energy for the dd -> He-4 eta reaction ranging from Q = 70 MeV to Q = 30 MeV. The luminosity was determined based on the dd -> (3)Hen reaction and the quasi-free proton proton scattering via dd -> ppn(spectator)n(spectator) reactions. The excitation functions, determined independently for the measured reactions, do not reveal a structure which could be interpreted as a narrow mesic nucleus. Therefore, the upper limits of the total cross sections for the bound state production and decay in dd -> (4He-eta)(bound) -> (3)Hen pi(0) and dd -> (He-4-eta)(bound) -> (3)Hep pi(-) processes were determined taking into account the isospin relation between the both of the considered channels. The results of the analysis depend on the assumptions of the N* (1535) momentum distribution in the anticipated mesic-He-4. Assuming, as in the previous works, that this is identical with the distribution of nucleons bound with 20 MeV in He-4, we determined that (for the mesic bound state width in the range from 5 MeV to 50 MeV) the upper limits at 90% confidence level are about 3 nb and about 6 nb for n pi(0) and p pi(-) channels, respectively. However, based on the recent theoretical findings of the N*(1535) momentum distribution in the N*-He-3 nucleus bound by 3.6 MeV, we find that the WASA-at-COSY detector acceptance decreases and hence the corresponding upper limits are 5 nb and 10 nb for n pi(0) and p pi(-) channels respectively. (C) 2017 Elsevier B.V. All rights reserved.
Spectroscopic study of prompt-gamma emission for range verification in proton therapy
L. Kelleter, A. Wronska, J. Besuglow, A. Konefal, K. Laihem, J. Leidner, A. Magiera, K. Parodi, K. Rusiecka, A. Stahl, T. Tessonnier
abstract
We present the results of an investigation of the prompt-gamma emission from an interaction of a proton beam with phantom materials. Measurements were conducted with a novel setup allowing the precise selection of the investigated depth in the phantom, featuring three different materials composed of carbon, oxygen and hydrogen. We studied two beam energies of 70.54 and 130.87 MeV and two detection angles: 90 degrees and 120 degrees. The results are presented in form of profiles of the prompt-gamma yield as a function of depth. In the analysis we focused on the transitions with the largest cross sections: C-12(4.44 -> g.s.) and O-16(6.13 -> g.s). We compare the profiles obtained under various irradiation conditions, with emphasis on the shape of the distal fall-off. The results are also compared to calculations including different cross-section models. They are in agreement with the model exploiting published cross-section data, but the comparison with the TALYS model shows discrepancies. (C) 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
Measurements of branching ratios for eta decays into charged particles
P. AdlarsoN, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, et al.
abstract
The WASA-at-COSY experiment has collected 3 x 10(7) events with eta mesons produced via the reaction pd -> He-3 eta at T = 1.0 GeV. Using this data set, we evaluate the branching ratios of the decays eta -> pi(+)pi(-)gamma, eta -> e(+)e(-)gamma, eta -> pi(+)pi(-)e(+)e(-), and eta -> e(+)e(-)e(+)e(-). The branching ratios are normalized to the eta -> pi(+)pi(-) pi(0) decay. In addition an upper limit on a CP-violating asymmetry in eta -> pi(+)pi(-)e(+)e(-) is extracted.
Search for an isospin I=3 dibaryon
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhnl, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Various theoretical calculations based on QCD or hadronic interactions predict that in addition to the recently observed dibaryon resonance d*(2380) with I(J(P)) = 3(0(+)) there should also exist a dibaryon resonance with mirrored quantum numbers I(J(P)) = 3(0(+)). We report here on a search for such a NN-decoupled state in data on the pp -> pp pi(+) pi(+) pi(-) pi(-) reaction. Since no clear-cut evidence has been found, we give upper limits for the production cross section of such a resonance in the mass range 2280-2500 MeV. (C) 2016 The Author(s). Published by Elsevier B.V.
Experimental study of the pd (dp) -> He-3 pi pi reactions close to threshold
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, R. Joosten, K. Kilian, A. Kozela, H. Machner, A. Magiera, J. Munkel, P. von Neumann-Cosel, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, R. Tolle, C. Wilkin
abstract
New experimental data on the pd -> He-3 pi(+)pi(-) reaction obtained with the COSY-MOMO detector below the three-pion threshold are presented. The reaction was also studied in inverse kinematics with a deuteron beam and the higher counting rates achieved were especially important at low excess energies. The comparison of these data with inclusive pd -> He-3 X-0 rates allowed estimates also to be made of pi(0)pi(0) production. The results confirm our earlier findings that, close to threshold, there is no enhancement at low excitation energies in the pi(+)pi(-) system, where the data seem largely suppressed compared with phase space. Possible explanations for this behavior, such as strong p waves in the pi(+)pi(-) system or the influence of two-step processes, are explored.
How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97-GeV/c Deuterons in a Storage Ring
G. Guidoboni, E. Stephenson, S. Andrianov, W. Augustyniak, Z. Bagdasarian, M. Bai, M. Baylac, W. Bernreuther, S. Bertelli, M. Berz, J. Boker, C. Bohme, J. Bsaisou, S. Chekmenev, D. Chiladze, G. Ciullo, M. Contalbrigo, JM. de Conto, S. Dymov, R. Engels, FM. Esser, D. Eversmann, O. Felden, M. Gaisser, R. Gebel, H. Gluckler, F. Goldenbaum, K. Grigoryev, D. Grzonka, T. Hahnraths, D. Heberling, V. Hejny, N. Hempelmann, J. Hetze, F. Hinder, R. Hipple, D. Holscher, A. Ivanov, A. Kacharava, V. Kamerdzhiev, B. Kamys, I. Keshelashvili, A. Khoukaz, I. Koop, HJ. Krause, S. Krewald, A. Kulikov, A. Lehrach, P. Lenisa, N. Lomidze, B. Lorentz, P. Maanen, G. Macharashvili, A. Magiera, R. Maier, K. Iviakino, B. Marianski, D. Mchedlishvili, UG. Meissner, S. Mey, W. Morse, F. Mueller, A. Nass, G. Natour, N. Nikolaev, M. Nioradze, et al.
abstract
We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10(-29) e cm.
Measurement of the (n)over-right-arrowp -> d pi(0) pi(0) reaction with polarized beam in the region of the d(*)(2380) resonance
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Caleen, I. Ciepa, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Foohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, V. Serdyuk, et al.
abstract
We report on a high-statistics measurement of the most basic double-pionic fusion reaction over the energy region of the d (*)(2380) resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the d(*) resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.
DEUTERON-DEUTERON COLLISION AT 160 MeV
G. Khatri, W. Parol, K. Bodek, I. Ciepal, B. Jamroz, N. Kalantar-Nayestanaki, S. Kistryn, B. Klos, A. Kozela, P. Kulessa, A. Magiera, I. Mazumdar, JG. Messchendorp, D. Rozpedzik, I. Skwira-Chalot, E. Stephan, A. Wilczek, B. Wloch, A. Wronska, J. Zejma
abstract
The experiment was carried out using BINA detector at KVI in Groningen. For the first time, an extensive analysis of the data collected in back part of the detector is presented, where a clusterization method is utilized for angular and energy information. We also present differential cross sections for the (dd -> dpn) breakup reaction within dp quasi-free scattering limit and their comparison with first calculations based on Single Scattering Approximation (SSA) approach.
Experimental study of Three-Nucleon Dynamics in the dp breakup reaction
B. Klos, I. Ciepal, G. Khatri, S. Kistryn, A. Kozela, A. Magiera, W. Paroi, I. Skwira-Chalot, E. Stephan, K. Szpik
abstract
An experiment to investigate the H-1(d,pp)n breakup reaction using a deuteron beam of 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Jtilich. The main goal was a detailed study of various aspects of few nucleon dynamics like the three nucleon force (3NF), the long-range Coulomb interaction or relativistic effects in the medium energy region. The relativistic effects and their interplay with 3NF become more important with increasing available energy in the three nucleon system. The almost 47r geometry of the WASA detector provides an unique possibility to study various aspects of dynamics. The studies of the 3N system dynamics in the breakup reaction with BINA detector are continued in the Cyclotron Center Bronowice.
Experimental study of three-nucleon dynamics in the dp breakup collisions using the WASA detector
B. Klos, I. Ciepal, G. Khatri, S. Kistryn, A. Kozela, A. Magiera, W. Parol, I. Skwira-Chalot, E. Stephan
abstract
An experiment to investigate the H-1(d, pp)n breakup reaction using a deuteron beam of 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Julich. The studied energy region, below but close to a pion production threshold, may provide information on various aspects of nuclear interactions, in particular on relativistic effects and their interplay with the three nucleon force (3NF). The almost 4 pi geometry of the WASA detector gives an unique possibility to study the different aspects of nucleon-nucleon dynamics in the three nucleon system. The main steps of the analysis, including energy calibration, PID and studied of efficiency, and their impact on final accuracy of the result, will be discussed.
Contribution of three nucleon force investigated in deuteron-proton breakup reaction
W. Parol, A. Kozela, I. Ciepal, K. Bodek, B. Jamroz, N. Kalantar-Nayestanaki, G. Khatri, S. Kistryn, B. Klos, J. Kubos, P. Kulessa, A. Magiera, I. Mazumdar, JG. Messchendorp, D. Rozpedzik, A. Rusnok, I. Skwira-Chalot, E. Stephan, A. Wilczek, B. Wloch, A. Wronska, J. Zejma
abstract
The elastic scattering and deuteron breakup data were collected in the experiment performed at KVI (Groningen) with use of unpolarized deuteron beam with energy of 80 MeV per nucleon, impinging on hydrogen target. The procedure applied to determine total integrated luminosity is presented. The result will be used for normalization of the differential cross section for the deuteron-proton breakup reaction.
Investigation of the Deuteron Breakup on Proton Target in the Forward Angular Region at 130 MeV
I. Ciepal, B. Klos, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, PU. Sauer, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witaa, J. Zejma
abstract
A set of differential cross-section data of the (1) H(d, pp)n breakup reaction at 130 MeV deuteron beam energy has been measured in the domain of very forward polar angles with the use of the Germanium Wall detector at the Forschungszentrum Julich. The data obtained for over 1000 kinematical points (112 geometries) are compared with the theoretical predictions based on various models of the three-nucleon (3N) dynamics. They comprise: the realistic nucleon-nucleon potentials alone or combined with the three-nucleon force (3NF), the coupled-channel calculations with the explicit treatment of the Delta-isobar excitation and finally, the potentials derived from chiral perturbation theory. In the part of the phase space studied, the Coulomb interaction between protons has a strong impact on the differential cross section of the breakup reaction. The strongest Coulomb effects are found in regions where the relative energy of the two protons is the smallest. In these regions the data are well reproduced exclusively by calculations which include the electromagnetic repulsion between protons. In spite of the dominance of the Coulomb force in the phase space studied, the contribution of 3NF effects is also observed.
New Method for a Continuous Determination of the Spin Tune in Storage Rings and Implications for Precision Experiments
D. Eversmann, V. Hejny, F. Hinder, A. Kacharava, J. Pretz, F. Rathmann, M. Rosenthal, F. Trinkel, S. Andrianov, W. Augustyniak, Z. Bagdasarian, M. Bai, W. Bernreuther, S. Bertelli, M. Berz, J. Bsaisou, S. Chekmenev, D. Chiladze, G. Ciullo, M. Contalbrigo, J. de Vries, S. Dymov, R. Engels, FM. Esser, O. Felden, M. Gaisser, R. Gebel, H. Gluckler, F. Goldenbaum, K. Grigoryev, D. Grzonka, G. Guidoboni, C. Hanhart, D. Heberling, N. Hempelmann, J. Hetzel, R. Hipple, D. Holscher, A. Ivanov, V. Kamerdzhiev, B. Kamys, I. Keshelashvili, A. Khoukaz, I. Koop, HJ. Krause, S. Krewald, A. Kulikov, A. Lehrach, P. Lenisa, N. Lomidze, B. Lorentz, P. Maanen, G. Macharashvili, A. Magiera, R. Maier, K. Makino, B. Marianski, D. Mchedlishvili, UG. Meiner, S. Mey, A. Nass, G. Natour, N. Nikolaev, M. Nioradze, A. Nogga, K. Nowakowski, A. Pesce, et al.
abstract
A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by nu(s) = gamma G (gamma is the Lorentz factor, G the gyromagnetic anomaly). At 970 MeV/c, the deuteron spins coherently process at a frequency of approximate to 120 kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10(-8), and to 1 x 10(-10) for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
Experimental Investigation of Few-Nucleon Dynamics at Medium Energies
G. Khatri, K. Bodek, I. Ciepal, N. Kalantar-Nayestanaki, S. Kistryn, B. Klos, A. Kozela, A. Magiera, I. Mazumdar, JG. Messchendorp, W. Parol, D. Rozpedzik, I. Skwira-Chalot, E. Stephan, A. Wronska, J. Zejma
abstract
An experiment, with unpolarized deuteron beam of 160 MeV impinging on liquid hydrogen and liquid deuterium targets, was carried out using BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-section for the deuteron break-up reaction. The elastic scattering data were also collected alongside. We present here the methods applied in analysis of data collected in the backward part of the detector.
Measurement of the np -> np pi(0)pi(0) reaction in search for the recently observed d* (2380) resonance
P. Adlarsona, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, B. Hoistad, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, P. Podkopal, D. Prasuhn, A. Pricking, D. Pszczel, K. Pysz, et al.
abstract
Exclusive measurements of the quasi-free np --> np pi(0)pi(0) reaction have been performed by means of dp collisions at T-d = 2.27 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region root s = (2.35-2.46) GeV, which includes the region of the ABC effect and its associated d* (2380) resonance. Adding the d* resonance amplitude to that for the conventional processes leads to a reasonable description of the data. The observed resonance effect in the total cross section is in agreement with the predictions of Faldt and Wilkin as well with those of Albadajedo and Oset. The ABC effect, i.e. the low-mass enhancement in the pi(0)pi(0)-invariant mass spectrum, is found to be very modest - if present at all, which might pose a problem to some of its interpretations. (C) 2015 The Authors. Published by Elsevier B.V.
GAMMA EMISSION IN HADRON THERAPY - EXPERIMENTAL APPROACH
A. Wronska, P. Bednarczyk, D. Bockenhoff, A. Bubak, S. Feyen, A. Konefal, K. Laihem, A. Magiera, A. Stahl, M. Zieblinski
abstract
Experiment Gamma-CCB at the Cyclotron Centre Bronowice focuses on investigation of gamma emission in experimental modelling of hadron therapy, searching for manifestation of the Bragg peak in gamma spectra. Experimental program comprises a series of measurements for different energies of the beam accelerated in the cyclotron Proteus C-235, as well as for several phantom materials. The paper reports on the results of the first measurements performed at 70 MeV proton beam energy and for two target materials: graphite and polymethyl methacrylate PMMA. Two different experimental techniques were tested, resulting in differential gamma spectra or spectra integrated over whole proton penetration path in a phantom. Strong correlation of the intensity of the carbon and oxygen excitation lines with the Bragg peak position has been observed in both types of measurements, confirming potential of the method in the future application in hadron therapy.
COULOMB FORCE EFFECTS IN DEUTERON-PROTON BREAKUP REACTION
I. Ciepal, B. Klos, A. Kozela, E. Stephan, S. Kistryn, A. Biegun, K. Bodek, A. Deltuva, M. Eslami-Kalantari, V. Jha, N. Kalantar-Nayestanaki, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, M. Kravcikova, P. Kulessa, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, I. Skwira-Chalot, R. Sworst, J. Urban, J. Zejma
abstract
A large set of cross-section data for the H-1 (d,pp)n breakup reaction was measured at 130 MeV deuteron beam energy with the Germanium Wall setup covering the range of very forward polar angles. In the investigated part of the phase-space, the dynamics is dominated by the Coulomb force influence. The data are compared with results of theoretical calculations based on the realistic Argonne V18 potential supplemented with the long-range electromagnetic component. The predictions also include the Urbana IX three nucleon force model. The cross-section data reveal seizable Coulomb force effects.
Gamma Emission in Hadron Therapy - Towards New Tools of Quality Assurance
A. Wronska, P. Bednarczyk, D. Bockenhoff, A. Bubak, S. Feyen, A. Konefal, L. Kelleter, K. Laihem, J. Leidner, A. Magiera, G. Obrzud, K. Rusiecka, A. Stahl, M. Zieblinski
abstract
The Gamma-CCB experiment is focused on investigation of gamma emission in experiments modeling the course of hadron therapy. The main goal is to search for manifestation of the Bragg peak in the prompt gamma spectra. Experimental program comprises a series of measurements at different proton beam energies and for various phantom materials. In the two beam times performed by the group so far in CCB Cracow and HIT Heidelberg, data were taken with proton beam energy of 70 and 130 MeV and with three phantom materials: graphite, poly(methyl methacrylate) PMMA and polyoxymethylene POM, in order to study effects from different elements forming human tissue. Two different measurement modes were tested. In the first mode the gamma spectrum integrated over the whole beam penetration path in the phantom was registered, in the other mode only the gamma quanta originating in a phantom slice at a certain depth. In both measurement modes we observe strong correlation of the intensity of the carbon and oxygen excitation lines (4.44 and 6.13 MeV, respectively) with the Bragg peak position. Moreover, the correlation was found to be far more pronounced at backward angles than at the 90 degrees polar angle studied so far.
Measurement of the eta -> pi(+)pi(-)pi(0) Dalitz plot distribution
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, M. Hodana, B. Hoistad, N. Husken, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, BV. Martemyanov, UG. Meissner, M. Mikirtychiants, HP. Morsch, P. Moskal, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, et al.
abstract
The Dalitz plot distribution of the eta -> pi(+)pi(-)pi(0) decay is determined by using a data sample of 1.2 x 10(7) eta mesons from the pd -> He-3 eta reaction at 1 GeV collected by the WASA detector at COSY.
Investigation of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction
I. Ciepal, B. Klos, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witała, J. Zejma
abstract
Precise and large sets of cross section, vector A (x) , A (y) and tensor A (xx) , A (xy) , A (yy) analyzing power data for the (1) H(d, pp)n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the SALAD and BINA detectors at KVI and the Germanium Wall setup at FZ-Julich. Results are compared with various theoretical approaches which model the three-nucleon system dynamics. The cross section data reveal a sizable three-nucleon force (3NF) and Coulomb force influence. In case of the analyzing powers very low sensitivity to these effects was found and the data are well describe by 2N models only. For A (xy) at 130 MeV, serious disagreements were observed when 3NF models are included in the calculations.
Systematic Study of Three-Nucleon Systems Dynamics in the Cross Section of the Deuteron-Proton Breakup Reaction
B. Klos, I. Ciepal, B. Jamroz, G. Khatri, S. Kistryn, A. Kozela, A. Magiera, W. Parol, I. Skwira-Chalot, E. Stephan
abstract
An experiment to investigate the H-1(d, pp)n breakup reaction using a deuteron beam of 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Julich. The main goal was the detailed study of various aspects of few-nucleon dynamics in the medium energy region, with particular emphasis on relativistic effects and their interplay with three nucleon forces. These effects become more important with increasing available energy in the three nucleon system. Therefore the investigations at high energies are crucial to understand their nature. The almost 4 pi geometry of the WASA detector gives an unique possibility to study various aspects of dynamics of processes in the three-nucleon reaction. Preliminary results obtained using the WASA detector are presented.
Few-Nucleon System Dynamics Studied via Deuteron-Deuteron Breakup Reactions at 160 MeV
G. Khatri, I. Ciepal, K. Bodek, N. Kalantar-Nayestanaki, S. Kistryn, B. Klos, A. Kozela, A. Magiera, I. Mazumdar, J. Messchendorp, W. Parol, I. Skwira-Chalot, E. Stephan, D. Rozpedzik, A. Wronska, J. Zejma
abstract
An experiment, with the deuteron beams at energy of 160 MeV impinging on the liquid deuterium target, was carried out using the BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-sections for the deuteron break-up reaction. The elastic scattering channel was also measured alongside for the purpose of cross-section normalization.
Sequential and simultaneous emission of particles from p plus Al collisions at GeV energies
M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, A. Jany, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, SK. Sharma, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE were measured for p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11 produced in collisions of 1.2, 1.9, and 2.5 GeV protons with an Al target. It was found that the cross sections are almost independent of the beam energy. The spectra and angular distributions indicate a presence of two contributions: a quasi-isotropic, low-energy one which is attributed to the emission of particles from excited remnants of the intranuclear cascade, and an anisotropic part which is interpreted to originate from the first stage of the reaction. The experimental data are compared with an intranuclear cascade model coupled to evaporation, and to statistical multifragmentation models using their standard parameter settings. It was found that all applied models produce very similar results describing spectra of the intermediate mass fragments. All models also reproduce well the low-energy part of the spectra of light charged particles (below approximate to 30 MeV). The description of the higher energy part (50-150 MeV) of the light charged particles spectra is poorer, deteriorating with decreasing scattering angle and decreasing mass of the particles.
Investigation of three nucleon force effects in deuteron-proton breakup reaction
W. Parol, I. Ciepal, K. Bodek, S. Kistryn, G. Khatri, A. Magiera, D. Rozpedzik, A. Wronska, J. Zejma, B. Klos, E. Stephan, A. Kozela, P. Kulessa, N. Kalantar-Nayestanaki, J. Messchendorp, I. Mazumdar, I. Skwira-Chalot
abstract
Experiments devoted to study subtle ingredients of nuclear dynamics were carried out at KVI in Groningen with the use of the H-1(d,pp)n breakup reaction at the deuteron beam energy of 80 MeV/nucleon. The aim of the work is to determine the breakup cross sections and confront them with the set of modern calculations which model forces acting between nucleons. Elastic scattering process was also measured for the purpose of the cross section normalization. This paper presents preliminary results of the data analysis including geometry cross check, energy calibration, particles identification and sample distributions of the unnormalized breakup cross sections.
Investigation of three nucleon force effects in deuteron-proton breakup reaction India
W. Parol, A. Kozela, I. Ciepal, B. Klos, K. Bodek, J. Golak, N. Kalantar-Nayestanaki, G. Khatri, S. Kistryn, P. Kulessa, A. Magiera, I. Mazumdar, J. Messchendorp, D. Rozpedzik, R. Skibiński, I. Skwira-Chalot, E. Stephan, H. Witała, A. Wronska, J. Zejma
abstract
Experimental study of the deuteron-proton breakup process was perfomed in KVI Groningen. In this paper current status of the collected data analysis is presented, including preliminary results of the cross section for the sample kinematical configuration.
Studies of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction
I. Ciepal, B. Klos, E. Stephan, S. Kistryn, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibinski, R. Sworst, J. Urban, H. Witala, J. Zejma
abstract
One of the most important goals of modern nuclear physics is to contruct nuclear force model which properly describes the experimental data. To develop and test predictions of current models the breakup 1H(d(->), pp)n reaction was investigated experimentally at 100 and 130 MeV deuteron beam energies. Rich set of data for cross section, vector and tensor analyzing powers was obtained with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Julich. Results are compared with various theoretical approaches which describe the three-nucleon (3N) system dynamics. For correct description of the cross section data both, three-nucleon force (3NF) and Coulomb force, have to be included into calculations and influence of those ingredients is seizable at specific parts of the phase space. In case of the vector analyzing powers very low sensitivity to any effects beyond nucleon-nucleon interaction was found. At 130 MeV, the A(xy) data are not correctly described when 3NF models are included into calculations.
Experimental study of relativistic effects in the dp breakup reaction using the WASA detector
B. Klos, I. Ciepal, B. Jamroz, G. Khatri, S. Kistryn, A. Kozela, A. Magiera, W. Parol, I. Skwira-Chalot, E. Stephan
abstract
An experiment to investigate the H-1((sic) pp)n breakup reaction at 340 MeV, 360 MeV and 400 MeV deuteron beam energy has been performed at the Cooler Synchrotron COSY-Julich with the WASA detecr. The main goal was to study of various aspects of few-nucleon dynamics in the medium energy region, with a particular emphasis on relativistic effects and their interplay with three nucelon forces. The almost 4 pi geometry of the WASA detector gives an unique possibility to study the different aspects of nucleon-nucleon dynamics in the three nucleon system. The preliminary analysis of the collected data is presented.
Experimental Investigation of the Few-Nucleon Dynamics in Deuteron-Deuteron Collision at 160 MeV
G. Khatri, K. Bodek, I. Ciepal, N. Kalantar-Nayestanaki, S. Kistryn, B. Klos, A. Kozela, A. Magiera, I. Mazumdar, J. Messchendorp, W. Parol, D. Rozpedzik, I. Skwira-Chalot, E. Stephan, A. Wronska, J. Zejma
abstract
An experiment, with unpolarized deuteron beam of 160 MeV impinging on liquid deuterium target, was carried out using BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-section for the deuteron break-up reaction. The elastic scattering data were also collected alongside for the purpose of cross-section normalization. We present here a sample of the un-normalised cross-section for the three-body final state (dd -> dpn) reaction.
Investigation of three nucleon force effects in deuteron-proton breakup reaction India
W. Parol, A. Kozela, I. Ciepal, B. Klos, K. Bodek, J. Golak, N. Kalantar-Nayestanaki, G. Khatri, S. Kistryn, P. Kulessa, A. Magiera, I. Mazumdar, J. Messchendorp, D. Rozpedzik, R. Skibinski, I. Skwira-Chalot, E. Stephan, H. Witala, A. Wronska, J. Zejma
abstract
Experimental study of the deuteron-proton breakup process was perfomed in KVI Groningen. In this paper current status of the collected data analysis is presented, including preliminary results of the cross section for the sample kinematical configuration.
Studies of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction
I. Ciepal, B. Klos, E. Stephan, S. Kistryn, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witała, J. Zejma
abstract
One of the most important goals of modern nuclear physics is to contruct nuclear force model which properly describes the experimental data. To develop and test predictions of current models the breakup 1H(d(->), pp)n reaction was investigated experimentally at 100 and 130 MeV deuteron beam energies. Rich set of data for cross section, vector and tensor analyzing powers was obtained with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Julich. Results are compared with various theoretical approaches which describe the three-nucleon (3N) system dynamics. For correct description of the cross section data both, three-nucleon force (3NF) and Coulomb force, have to be included into calculations and influence of those ingredients is seizable at specific parts of the phase space. In case of the vector analyzing powers very low sensitivity to any effects beyond nucleon-nucleon interaction was found. At 130 MeV, the A(xy) data are not correctly described when 3NF models are included into calculations.
Measurement of the pn -> pp pi(0)pi(-) reaction in search for the recently observed resonance structure in d pi(0)pi(0) and d pi(+)pi(-) systems
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, DA. Kirillov, S. Kistryn, J. Klaja, H. Kleines, B. Klos, M. Krapp, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, P. Plucinski, P. Podkopal, et al.
abstract
Exclusive measurements of the quasifree pn -> pp pi(0)pi(-) reaction have been performed by means of pd collisions at T-p = 1.2 GeV using the wide angle shower apparatus (WASA) detector setup at the cooler synchrotron COSY (Institut fur Kernphysik, Julich). Total and differential cross sections have been obtained covering the energy region root s = (2.35-2.46) GeV, which includes the region of the ABC effect and its associated resonance structure. NoABCeffect, i.e., low-mass enhancement is found in the pi(0)pi(-) -invariant mass spectrum, in agreement with the constraint from Bose statistics that the isovector pion pair can not be in relative s wave. At the upper end of the covered energy region t-channel processes for Roper, Delta(1600) and Delta Delta excitations provide a reasonable description of the data, but at low energies the measured cross sections are much larger than predicted by such processes. Adding a resonance amplitude for the resonance at m = 2.37 GeV with Gamma = 70 MeV and I (J(P)) = 0(3(+)) observed recently in pn -> d pi(0)pi(0) and pn -> d pi(+)pi(-) reactions leads to an agreement with the data also at low energies.
Search for a dark photon in the pi(0) -> e(+)e(-)gamma decay
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, E. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauensteinn, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, DA. Kirillov, B. Klos, M. Krapp, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, UG. Meissner, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, H. Ohm, I. Ozerianska, EP. del Rio, et al.
abstract
The presently world largest data sample for pi(0) -> gamma e(+)e(-) decays studies containing nearly 5 x 10(5) events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi(0) -> gamma U -> gamma e(+)e(-) decay from the pp -> pp pi(0) reaction was carried out. An upper limit on the square of the U -> gamma mixing strength parameter epsilon(2) of 5 x 10(-6) at 90% CL was obtained for the mass range 20 MeV < M-U < 100 MeV. This result together with other recent experimental limits significantly reduces the M-U vs. epsilon(2) parameter space which could explain the presently seen deviation between the Standard Model prediction and the direct measurement of the anomalous magnetic moment of the muon. (C) 2013 Elsevier B.V. All rights reserved.
Investigations of Few-Nucleon System Dynamics in Medium Energy Domain
I. Ciepal, B. Klos, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witała, A. Wronska, J. Zejma
abstract
Precise and large set of cross sections, vector A (x) , A (y) and tensor A (xx) , A (xy) , A (yy) analyzing powers for the (1) H(d, pp)n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Julich. Results are compared with various theoretical approaches which model the three-nucleon (3N) system dynamics. The calculations are based on different two-nucleon (2N) potentials which can be combined with models of the three-nucleon force (3NF) and other pieces of the dynamics can also be included like the Coulomb interaction and relativistic effects. The cross sections data reveal seizable 3NF and Coulomb force influence. In case of analyzing powers very low sensitivity to the effects was found and the data are well describe by 2N models only. At 130 MeV for A (xy) serious disagreements appear when 3NF models are included into calculations.
Investigation of the dd -> (3)Hen pi(0) reaction with the FZ Julich WASA-at-COSY facility
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, C. Hanhart, F. Hauenstein, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, DA. Kirillov, S. Kistryn, J. Klaja, H. Kleines, B. Klos, M. Krapp, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, P. Plucinski, et al.
abstract
An exclusive measurement of the dd -> (3)Hen pi(0) reaction was carried out at a beam momentum of p(d) = 1.2 GeV/c using the WASA-at-COSY facility. Information on the total cross section as well as differential distributions was obtained. The data are described by a phenomenological approach based on a combination of a quasifree model and a partial wave expansion for the three-body reaction. The total cross section is found to be sigma(tot) = ( 2.89 +/- 0.01(stat) +/- 0.06(sys) +/- 0.29(norm)) mu b. The contribution of the quasifree processes ( with the beam or target neutron being a spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of phase space. The remaining part of the cross section can be described by a partial wave decomposition indicating the significance of p-wave contributions in the final state.
Isospin decomposition of the basic double-pionic fusion in the region of the ABC effect
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, FS. Bergmann, M. Berlowski, H. Bhatt, M. Buscher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, M. Krapp, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, S. Niedzwiecki, H. Ohm, I. Ozerianska, EP. del Rio, P. Plucinski, P. Podkopal, et al.
abstract
Exclusive and kinematically complete high-statistics measurements of the basic double-pionic fusion reactions pn -> d pi(0)pi(0), pn -> d pi(+)pi(-) and pp -> d pi(+)pi(0) have been carried out simultaneously over the energy region of the ABC effect using the WASA detector setup at COSY. Whereas the isoscalar reaction part given by the d pi(0)pi(0) channel exhibits the ABC effect, i.e. a low-mass enhancement in the pi pi-invariant mass distribution, as well as the associated resonance structure in the total cross section, the isovector part given by the d pi(+)pi(0) channel shows a smooth behavior consistent with the conventional t-channel Delta Delta process. The d pi(+)pi(-) data are very well reproduced by combining the data for isovector and isoscalar contributions, if the kinematical consequences of the isospin violation due to different masses for charged and neutral pions are taken into account. (C) 2013 Elsevier B.V. All rights reserved.
Study of the Lambda p interaction close to the Sigma(+)n and Sigma(0)p thresholds
H. Machner, J. Haidenbauer, F. Hinterberger, A. Magiera, JA. Niskanen, J. Ritman, R. Siudak
abstract
The Lambda p interaction close to the Sigma N threshold is considered. Specifically, the pronounced structure seen in production reactions like K(-)d -> pi(-)Lambda p and pp -> K+Lambda p around the Sigma N threshold is analyzed. Modern interaction models of the coupled Lambda N-Sigma N systems generate such a structure either due to the presence of a (deuteron-like) unstable bound state or of an inelastic virtual state. A determination of the position of the prominent peak as observed in various experiments for the two aforementioned reactions leads to values that agree quite well with each other. Furthermore, the deduced mean value of 2128.7 +/- 0.3 MeV for the peak position coincides practically with the threshold energy of the Sigma(+)n channel. This supports the interpretation of the structure as a genuine cusp, signaling an inelastic virtual state in the S-3(1)-D-3(1) partial wave of the Sigma N isospin 1/2 channel. There is also evidence for a second peak (or shoulder) in the data sets considered which appears at roughly 10-15 MeV above the Sigma N threshold. However, its concrete position varies significantly from data set to data set and, thus, a theoretical interpretation is difficult. (c) 2013 Elsevier B.V. All rights reserved.
SYSTEMATIC STUDIES OF THE THREE-NUCLEON SYSTEM DYNAMICS IN THE DEUTRON-PROTON BREAKUP REACTION
B. Klos, I. Ciepal, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, B. Jamroz, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibinski, R. Sworst, J. Urban, H. Witala, A. Wronska, J. Zejma
abstract
Precise and large sets of data for cross section, vector and tensor analyzing powers for the H-1((d) over right arrow ,pp)n breakup reaction were obtained in experiments carried out at KVI Groningen and FZ-Julich at deuteron beam energies of 100 MeV, 13 MeV and 160 MeV (cross sections only). These precise experimental data obtained in a wide phase-space region allowed to establish evidences for three-nucleon force contributions and to confirm predictions of sizable effect of the Coulomb force. The vector analyzing powers data are generally quite well described by theoretical predictions even with pure nucleon nucleon interactions. Tensor analyzing powers can be also very well reproduced by calculations in most of the studied region but in some regions locally discrepancies are observed at energy of 130 MeV. DOI:10.5506/APhysPolB.44.345
SYSTEMATIC STUDIES OF THE THREE-NUCLEON SYSTEM DYNAMICS IN THE DEUTRON-PROTON BREAKUP REACTION
B. Klos, I. Ciepal, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, B. Jamroz, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witała, A. Wronska, J. Zejma
abstract
Precise and large sets of data for cross section, vector and tensor analyzing powers for the H-1((d) over right arrow ,pp)n breakup reaction were obtained in experiments carried out at KVI Groningen and FZ-Julich at deuteron beam energies of 100 MeV, 13 MeV and 160 MeV (cross sections only). These precise experimental data obtained in a wide phase-space region allowed to establish evidences for three-nucleon force contributions and to confirm predictions of sizable effect of the Coulomb force. The vector analyzing powers data are generally quite well described by theoretical predictions even with pure nucleon nucleon interactions. Tensor analyzing powers can be also very well reproduced by calculations in most of the studied region but in some regions locally discrepancies are observed at energy of 130 MeV. DOI:10.5506/APhysPolB.44.345
Search for the eta-mesic 4He with WASA-at-COSY detector
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, FS. Bergmann, M. Berlowski, H. Bhatt, M. Buscher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, M. Krapp, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, S. Niedzwiecki, H. Ohm, I. Ozerianska, EP. del Rio, P. Plucinski, P. Podkopal, et al.
abstract
An exclusive measurement of the excitation function for the dd->3Heppi- reaction was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta meson production in the dd->4He-eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the 4He-eta system varied from -51.4MeV to 22MeV. The integrated luminosity in the experiment was determined using the dd->3Hen reaction. The shape of the excitation function for the dd->3Heppi- was examined. No signal of the 4He-eta bound state was observed. An upper limit for the cross-section for the bound state formation and decay in the process dd->(4He-eta)bound->3Heppi- was determined on the 90% confidence level and it varies from 20nb to 27nb for the bound state width ranging from 5MeV to 35MeV, respectively.
Abashian-Booth-Crowe resonance structure in the double pionic fusion to He-4
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, FS. Bergmann, M. Berlowski, H. Bhatt, KT. Brinkmann, M. Buscher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, C. Husmann, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, L. Li, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, S. Niedzwiecki, H. Ohm, I. Ozerianska, C. Pauly, EP. del Rio, Y. Petukhov, et al.
abstract
Exclusive and kinematically complete high-statistics measurements of the double pionic fusion reaction dd?4He?0?0 have been performed in the energy range 0.8?1.4 GeV covering thus the region of the Abashian-Booth-Crowe effect, which denotes a pronounced low-mass enhancement in the ?? invariant mass spectrum. The experiments were carried out with the WASA detector setup at the cooler synchrotron at Forshungszentrum Julich GmbH. Similar to the observation in the basic pn?d?0?0 reaction, the data reveal a correlation between the ABC effect and a resonancelike energy dependence in the total cross section. The maximum occurs at m=2.37 GeV + 2mN, i.e., at the same position as in the basic reaction. The observed resonance width ??160 MeV can be understood from broadening due to Fermi motion of the nucleons in initial and final nuclei together with collision damping. Differential cross sections are described equally well by the hypothesis of a pn resonance formation during the reaction process.
Technical Design Report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker
W. Erni, ..., S. Jowzaee, M. Kajetanowicz, B. Kamys, S. Kistryn, G. Korcyl, K. Korcyl, W. Krzemień, A. Magiera, P. Moskal, M. Palka, Z. Rudy, P. Salabura, J. Smyrski, A. Wrońska et al.
abstract
This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM-stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy-loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole Panda scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
Exclusive measurement of the eta->pi+ pi- gamma decay
P. Adlarson, C. Adolph, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, FS. Bergmann, M. Berlowski, H. Bhatt, KT. Brinkmann, M. Buscher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, CO. Gullstrom, C. Hanhart, L. Heijkenskjold, J. Heimlich, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, M. Jacewicz, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, F. Kren, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, S. Leupold, B. Lorentz, A. Magiera, R. Maier, B. Marianski, P. Marciniewski, UG. Meissner, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, S. Niedzwiecki, H. Ohm, A. Passfeld, C. Pauly, et al.
abstract
An exclusive measurement of the decay eta --> pi+ pi- gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd --> 3He X at a proton beam momentum of 1.7 GeV/c. Efficiency corrected differential distributions have been extracted based on 13340pm140 events after background subtraction. The measured pion angular distribution is consistent with a relative p-wave of the two-pion system, whereas the measured photon energy spectrum was found at variance with the simplest gauge invariant matrix element of eta --> pi+ pi- gamma. A parameterization of the data can be achieved by the additional inclusion of the empirical pion vector form factor multiplied by a first-order polynomial in the squared invariant mass of the pi+ pi- system.
pi0 pi0 Production in proton-proton collisions at Tp=1.4 GeV
P. Adlarson, C. Adolph, W. Augustyniak, M. Bashkanov, T. Bednarski, FS. Bergmann, M. Berlowski, H. Bhatt, KT. Brinkmann, M. Buscher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, J. Heimlich, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, M. Jacewicz, M. Janusz, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, F. Kren, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, B. Lorentz, A. Magiera, R. Maier, B. Marianski, P. Marciniewski, M. Mikirtychiants, HP. Morsch, P. Moskal, BK. Nandi, S. Niedzwiecki, H. Ohm, A. Passfeld, C. Pauly, EP. del Rio, Y. Petukhov, N. Piskunov, et al.
abstract
The reaction pp->pppi0pi0 has been investigated at a beam energy of 1.4 GeV using the WASA-at-COSY facility. The total cross section is found to be (324 +- 21_systematic +- 58_normalization) mub. In order to to study the production mechanism, differential kinematical distributions have been evaluated. The differential distributions indicate that both initial state protons are excited into intermediate Delta(1232) resonances, each decaying into a proton and a single pion, thereby producing the pion pair in the final state. No significant contribution of the Roper resonance N*(1440) via its decay into a proton and two pions is found
Studies of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction
I. Ciepal, B. Klos, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibinski, R. Sworst, J. Urban, H. Witala, A. Wronska, J. Zejma
abstract
Precise and large sets of cross sections for the H-1(d,pp)n and H-2(p,pp)n breakup reactions were measured at 130 deuteron and 190 MeV proton beam energies with the use of detectors which covered almost the full phase space. The results are compared with various theoretical approaches which model the 3N system dynamics. The calculations are based on different 2N potentials which can be combined with models of the three-nucleon force (3NF). The differential cross sections appear to be a very sensitive tool for testing the interaction models and allow to search for various ingredients of the dynamics, not only the 3NF but also the Coulomb interaction and relativistic effects which are relatively new achievements of the theory.
Investigation of the Charge Symmetry conserving reaction dd -> (3)Hen pi(0) with WASA-at-COSY
P. Podkopal, V. Hejny, A. Magiera, A. Wronska
abstract
The reaction dd -> (3)Hen pi(0) has been measured at a beam momentum of p(d) = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. The data are described with a phenomenological approach based on the combination of a quasi-free model and a partial wave expansion model for the three-body reaction.
Studies of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction
I. Ciepal, B. Klos, S. Kistryn, E. Stephan, A. Biegun, K. Bodek, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, J. Golak, V. Jha, N. Kalantar-Nayestanaki, H. Kamada, G. Khatri, D. Kirillov, D. Kirillov, S. Kliczewski, A. Kozela, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, J. Messchendorp, A. Nogga, W. Parol, A. Ramazani-Moghaddam-Arani, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witała, A. Wronska, J. Zejma
abstract
Precise and large sets of cross sections for the H-1(d,pp)n and H-2(p,pp)n breakup reactions were measured at 130 deuteron and 190 MeV proton beam energies with the use of detectors which covered almost the full phase space. The results are compared with various theoretical approaches which model the 3N system dynamics. The calculations are based on different 2N potentials which can be combined with models of the three-nucleon force (3NF). The differential cross sections appear to be a very sensitive tool for testing the interaction models and allow to search for various ingredients of the dynamics, not only the 3NF but also the Coulomb interaction and relativistic effects which are relatively new achievements of the theory.
Upper limits for a narrow resonance in the reaction p plus p -> K+ + (Lambda p)
A. Budzanowski, A. Chatterjee, H. Clement, P. Hawranek, F. Hinterberger, R. Jahn, R. Joosten, K. Kilian, D. Kirillov, D. Kirillov, S. Kliczewski, D. Kolev, M. Kravcikova, M. Lesiak, H. Machner, A. Magiera, G. Martinska, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, J. Roy, A. Sibirtsev, I. Sitnik, R. Siudak, R. Tsenov, K. Ulbrich, J. Urban, GJ. Wagner
abstract
The reaction pp -> K+ + (Lambda p) has been measured at T-p = 1.953 GeV and Theta = 0 degrees with a high missing-mass resolution in order to study the Lambda p final state interaction. Narrow S = -1 resonances predicted by bag model calculations are not visible in the missing-mass spectrum. Small structures observed in a previous experiment are not confirmed. Upper limits for the production cross section of a narrow resonance are deduced for missing masses between 2058 and 2105 MeV.
Abashian-Booth-Crowe effect in basic double fusion: A new resonance?
P. Adlarson, C. Adolph, W. Augustyniak, V. Baru, M. Bashkanov, T. Bednarski, FS. Bergmann, M. Berlowski, H. Bhatt, KT. Brinkmann, M. Buscher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, E. Doroshkevich, C. Ekstrom, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, V. Grishina, CO. Gullstrom, J. Hampe, C. Hanhart, L. Heijkenskjold, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, M. Jacewicz, M. Janusz, A. Jany, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, F. Kren, W. Krzemien, P. Kulessa, S. Kullander, A. Kupsc, K. Lalwani, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, P. Moskal, HP. Morsch, BK. Nandi, S. Niedzwiecki, H. Ohm, et al.
abstract
We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn->dpi0pi0 over the full energy region of the ABC effect, a pronounced low-mass enhancement in the pipi-invariant mass spectrum. The measurements, which cover also the transition region to the conventional t-channel DeltaDelta process, were performed with the upgraded WASA detector setup at COSY. The data reveal the Abashian-Booth-Crowe effect to be uniquely correlated with a Lorentzian energy dependence in the integral cross section. The observables are consistent with a narrow resonance with m=2.37??GeV, Gamma aprox 70 MeV and I(JP)=0(3+) in both pn and DeltaDelta systems. Necessary further tests of the resonance interpretation are discussed.
THREE-NUCLEON INTERACTION DYNAMICS STUDIED VIA THE DEUTERON-PROTON BREAKUP
E. Stephan, S. Kistryn, N. Kalantar-Nayestanaki, A. Biegun, K. Bodek, I. Ciepal, M. Eslami-Kalantari, V. Jha, DA. Kirillov, DI. Kirillov, M. Kis, S. Kliczewski, B. Klos, A. Kozela, M. Kravcikova, VM. Kyryanchuk, M. Lesiak, H. Machner, A. Magiera, M. Mahjour-Shafiei, G. Martinska, J. Messchendorp, A. Micherdzinska, N. Piskunov, D. Protic, A. Ramazani, P. Von Rossen, BJ. Roy, H. Sakai, K. Sekiguchi, I. Sitnik, R. Siudak, R. Sworst, J. Urban, J. Zejma, W. Zipper
abstract
Rich sets of high precision cross sections, vector and tensor analyzing powers for the H-1((d) over right arrow, pp)n breakup reaction were measured at 130 and 100 MeV beam energy with the use of detection systems covering large parts of the phase space. The cross section data allowed to establish evidences for three-nucleon force contributions and to confirm predictions of sizable effect of the Coulomb force in the breakup reaction. Analyzing power data are generally quite well described by theoretical predictions even with pure nucleon-nucleon interactions. However, in some regions discrepancies has been observed for tensor analyzing powers at 130 MeV.
Spin selectivity of dd -> alpha X reaction and its applications in hadron physics
A. Magiera
abstract
The dd -> alpha X reaction exhibits strong selectivity for the isospin, spin and parity of the X system. The charge symmetry requires that the X system should have isospin equal 0. The particle identity and conservations of the total angular momentum and parity impose very strong constraints on quantum numbers allowed in the reaction. This leads to very strong selectivity when a is emitted at 0 degrees or 180 degrees, as well as in the case of reactions at threshold. These features may be used to measure directly the individual partial wave contributions in the production reactions and to determine directly the spin and parity of the X system. Such kind of applications will be discussed for the charge symmetry forbidden dd -> alpha pi(0) reaction, the investigations of the sigma meson in the dd -> alpha sigma reaction and in studies of the dd -> alpha gamma reaction.
Experimental study of the p + Li-6 -> eta + Be-7 reaction 11.3 MeV above threshold
A. Budzanowski, A. Chatterjee, P. Hawranek, R. Jahn, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, R. Tsenov, J. Urban, G. Vankova
abstract
The cross section for the reaction p + Li-6 -> eta + Be-7 was measured at an excess energy of 11.28 MeV above threshold by detecting the recoiling Be-7 nuclei. A dedicated set of focal plane detectors was built for the magnetic spectrograph Big Karl and was used for identification and four-momentum measurement of Be-7. A differential cross section of d sigma/d Omega = [0.69 +/- 0.20(stat.) +/- 0.20(syst.)] nb/sr for the ground state plus 1/2(-) was measured. The result is compared to model calculations.
Comparison of nonequilibrium processes in p plus Ni and p plus Au collisions at GeV energies
A. Budzanowski, M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE were measured for p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8, Be-7,Be-9,Be-10, B-10,B-11, and C produced in collisions of 1.2, 1.9, and 2.5 GeV protons with a Ni target. The shape of the spectra and angular distributions almost does not change whereas the absolute value of the cross sections increases by a factor similar to 1.7 for all ejectiles in this beam energy range. It was found that energy and angular dependencies of the cross sections cannot be reproduced by microscopic models of intranuclear cascade including coalescence of nucleons coupled to statistical model for evaporation of particles from excited, equilibrated residual nuclei. The inclusion of nonequilibrium processes, described by a phenomenological model of the emission from fast and hot moving sources, resulting from break up of the target nucleus, leads to very good reproduction of data. Cross sections of these processes are quite large, exhausting approximately half of the total production cross sections. Due to good reproduction of energy and angular dependencies of d(2)sigma/d Omega dE it was possible to determine total production cross sections for all studied ejectiles. Results obtained in this work point to the analogous reaction mechanism for proton induced reactions on Ni target as that observed previously for Au target in the same beam energy range.
Cross sections of the pp -> K+ Sigma(+)n reaction close to threshold
A. Budzanowski, A. Chatterjee, H. Clement, E. Dorochkevitch, P. Hawranek, F. Hinterberger, R. Jahn, R. Joosten, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, H. Machner, A. Magiera, G. Martinska, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, A. Sibirtsev, I. Sitnik, R. Siudak, R. Tsenov, K. Ulbrich, J. Urban, GJ. Wagner
abstract
We have measured inclusive data on K+-meson production in pp collisions at COSY Julich close to the hyperon production threshold and determined the hyperon-nucleon invariant mass spectra. The spectra were decomposed into three parts: Lambda p, Sigma(0)p and Sigma(+)n. The cross section for the Sigma(+)n channel was found to be much smaller than a previous measurement in that excess energy region. The data together with previous results at higher energies are compatible with a phase space dependence. (C) 2010 Elsevier B.V. All rights reserved.
High resolution study of the Lambda p final state interaction in the reaction p plus p -> K+ (Lambda p) HIRES Collaboration
A. Budzanowski, A. Chatterjee, H. Clement, E. Dorochkevitch, P. Hawranek, F. Hinterberger, R. Jahn, R. Joosten, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, H. Machner, A. Magiera, G. Martinska, N. Piskunov, J. Ritman, P. von Rossen, BJ. Roy, A. Sibirtsev, I. Sitnik, R. Siudak, R. Tsenov, K. Ulbrich, J. Urban, GJ. Wagner
abstract
The reaction pp -> K+ (Ap) was measured at T-p = 1.953 GeV and Theta = 0 degrees with a high missing mass resolution in order to study the Ap final state interaction. The large final state enhancement near the Ap threshold can be described using the standard Jost-function approach. The singlet and triplet scattering lengths and effective ranges are deduced by fitting simultaneously the Ap invariant mass spectrum and the total cross section data of the free A p scattering. (C) 2010 Elsevier B.V. All rights reserved.
Variation of nonequilibrium processes in the p plus Ni system with beam energy
A. Budzanowski, M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE were measured for p,d,t,(3,4)He, (6,7)Li, (7,9)Be, and (10,11)B produced in collisions of 0.175 GeV protons with a Ni target. The analysis of measured differential cross sections allowed the extraction of total production cross sections for the ejectiles listed above. The shape of the spectra and angular distributions indicates the presence of other nonequilibrium processes besides the emission of nucleons from the intranuclear cascade and the evaporation of various particles from remnants of intranuclear cascade. These nonequilibrium processes consist of the coalescence of nucleons into light-charged particles during the intranuclear cascade, of the fireball emission, which contributes to the cross sections of protons and deuterons, and of the breakup of the target nucleus, which leads to the emission of intermediate mass fragments. All such processes were found earlier at beam energies 1.2, 1.9, and 2.5 GeV for Ni and Au targets; however, significant differences in the properties of these processes at high and low beam energy are observed in the present study.
Measurement of the eta -> 3 pi(0) Dalitz plot distribution with the WASA detector at COSY
C. Adolph, M. Angelstein, M. Bashkanov, U. Bechstedt, S. Belostotski, M. Berlowski, H. Bhatt, J. Bisplinghoff, A. Bondar, B. Borasoy, M. Buscher, H. Calen, K. Chandwani, H. Clement, E. Czerwinski, R. Czyzykiewicz, G. D'Orsaneo, D. Duniec, C. Ekstrom, R. Engels, W. Erven, W. Eyrich, P. Fedorets, O. Felden, K. Fransson, D. Gil, F. Goldenbaum, K. Grigoryev, A. Heczko, C. Hanhart, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, A. Izotov, M. Jacewicz, M. Janusz, BR. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, I. Keshelashvili, O. Khakimova, A. Khoukaz, K. Kilian, N. Kimura, S. Kistryn, J. Klaja, P. Klaja, H. Kleines, B. Klos, A. Kowalczyk, F. Kren, W. Krzemien, P. Kulessa, S. Kullander, A. Kupsc, A. Kuzmin, V. Kyryanchuk, J. Majewski, H. Machner, A. Magiera, R. Maier, R. Marciniewski, W. Migdal, UG. Meissner, et al.
abstract
In the first production run of the WASA experiment at COSY, the eta decay into three neutral pions was measured in proton-proton interactions at a proton beam kinetic energy of 1.4 GeV. The Dalitz plot of the three pious was Studied using 1.2 x 10(5) fully reconstructed events. and the quadratic slope parameter alpha was determined to be -0.027 +/- 0.008(stat) +/- 0.005(syst). The result is consistent with previous measurements and further corroborates the importance of pion-pion final state interactions. (C) 2009 Elsevier B.V. All rights reserved.
Precision measurements of the pp ->pi(+)pn and pp ->pi(+)d reactions: Importance of long-range and tensor force effects
A. Budzanowski, A. Chatterjee, P. Hawranek, F. Hinterberger, R. Jahn, V. Jha, K. Kilian, D. Kirillov, D. Kirillov, S. Kliczewski, D. Kolev, M. Kravcikova, M. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, JA. Niskanen, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, HJ. Stein, R. Tsenov, J. Urban, G. Vankova, C. Wilkin
abstract
Inclusive measurements of pion production in proton-proton collisions in the forward direction were undertaken at 400 and 600 MeV at the cooler synchrotron (COSY) at Forschungszentrum Julich using the Big Karl spectrograph. The high resolution in the pi(+) momentum ensured that there was an unambiguous separation of the pp ->pi(+)d/pi(+)pn channels. Using these and earlier data, the ratio of the production cross sections could be followed through the Delta region and compared with the predictions of final state interaction theory. Deviations are strongly influenced by long-range terms in the production operator and the tensor force in the final pn system. These have been investigated in a realistic pp ->pi(+)d/pi(+)pn calculation that includes S reversible arrow D channel coupling between the final nucleons. A semiquantitative understanding of the observed effects is achieved..
SEARCH OF eta-NUCLEUS BOUND STATE FORMATION IN RECOIL FREE TRANSFER REACTIONS
V. Jha, A. Budzanowski, A. Chatterjee, P. Hawranek, R. Jahn, BK. Jain, S. Kailas, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, J. Lieb, LC. Liu, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, P. Shukla, I. Sitnik, R. Siudak, R. Tsenov, J. Urban, G. Vankova
abstract
We have performed an experiment to search for the bound state of eta meson in nuclei. We have measured the reaction p+ (27)Al -> (3)He + p + pi(-) + X at recoil-free kinematics. An. meson possibly produced in this reaction would be thus almost at rest in the laboratory system and could therefore be bound with high probability, if bound nuclear. states exist. The decay of such a state through the N*(1535) resonance would lead to a proton-pi(-) pair emitted in opposite directions. For these conditions we find some indication of such a bound state. An upper limit of approximate to 0.5 nb for the formation cross section is found.
Cross section and tensor analysing power of the dd -> eta alpha reaction near threshold
A. Budzanowski, A. Chatterjee, R. Gebel, P. Hawranek, R. Jahn, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Prasuhn, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, R. Tsenov, J. Urban, G. Vankova, C. Wilkin
abstract
The angular distributions of the unpolarised differential cross section and tensor analysing power A(xx) of the (d) over right arrowd -> alpha eta reaction have been measured at an excess energy of 16.6 MeV. The ambiguities in the partial-wave description of these data are made explicit by using the invariant amplitude decomposition. This allows the magnitude of the s-wave amplitude to be extracted and compared with results published at lower energies. In this way, firmer bounds could be obtained on the scattering length of the eta alpha system. The results do not, however, unambiguously prove the existence of a quasi-bound eta alpha state. (C) 2009 Elsevier B.V. All rights reserved.
SEARCH FOR BOUND eta-NUCLEUS STATES
J. Urban, A. Budzanowski, A. Chatterjee, P. Hawranek, S. Kailas, BK. Jain, V. Jha, K. Kilian, S. Kliczewski, DA. Kirillov, DI. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, J. Lieb, LC. Liu, H. Machner, A. Magiera, R. Maier, G. Martinsk, S. Nedev, N. Piskunov, D. Protic, J. Ritman, P. Von Rossen, BJ. Roy, P. Shukla, I. Sitnik, R. Siudak, R. Tsenov, G. Vankova, C. Wilkin
abstract
The extracted s-wave scattering amplitude from both the polarized and unpolarized d + d -> (4)He + eta reaction at 2385.5 MeV/c allowed to determine the scattering length which fulfills the requirements for bound eta. In the p + (27)Al -> (3)He + p + pi(-) + X reaction studied at recoil free kinematics the eta meson is produced almost at rest and so it can be bound with enhanced probability. This state proceeds via N*(1535) resonance and the decay products proton and pion emitted into opposite direction are detected in concidence with (3)He produced at zero degree. Under these conditions some hints for bound state can be observed with an upper limit of the cross section of approximate to 0.5 nb.
THREE-NUCLEON INTERACTION DYNAMICS STUDIED VIA THE DEUTERON-PROTON BREAKUP
E. Stephan, S. Kistryn, N. Kalantar-Nayestanaki, A. Biegun, K. Bodek, I. Ciepal, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, W. Glockle, J. Golak, V. Jha, H. Kamada, D. Kirillov, D. Kirillov, M. Kis, S. Kliczewski, B. Klos, A. Kozela, M. Kravcikova, VM. Kyryanchuk, M. Lesiak, H. Machner, A. Magiera, M. Mahjour-Shafiei, G. Martinska, J. Messchendorp, A. Micherdzinska, A. Nogga, N. Piskunov, D. Protic, A. Ramazani, P. Von Rossen, BJ. Roy, H. Sakai, PU. Sauer, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibinski, R. Sworst, J. Urban, H. Witala, J. Zejma, W. Zipper
abstract
A large set of high precision cross sections, vector A(x), A(y) and tensor A(xx), A(xy), A(yy) analyzing powers for the (1)H((d) over right arrow ,pp)n breakup reaction were measured at 130 MeV beam energy with the detection system covering a large part of the phase space. Results are compared with rigorous theoretical calculations employing various models of the three-nucleon system dynamics. The cross section data allowed to establish evidence for three-nucleon force contributions and to confirm predictions of sizable effect of the Coulomb force in the breakup reaction. Analyzing power data are generally quite well described by theoretical predictions even with pure NN interactions. However, in some regions discrepancies has been observed for tensor analyzing powers, only rarely cured by inclusion of the three nucleon force. This indicates incompletness of the present-day treatment of the spin part of three nucleon system dynamics.
THREE-NUCLEON INTERACTION DYNAMICS STUDIED VIA THE DEUTERON-PROTON BREAKUP
E. Stephan, S. Kistryn, N. Kalantar-Nayestanaki, A. Biegun, K. Bodek, I. Ciepal, A. Deltuva, E. Epelbaum, M. Eslami-Kalantari, AC. Fonseca, W. Glockle, J. Golak, V. Jha, H. Kamada, D. Kirillov, D. Kirillov, M. Kis, S. Kliczewski, B. Klos, A. Kozela, M. Kravcikova, VM. Kyryanchuk, M. Lesiak, H. Machner, A. Magiera, M. Mahjour-Shafiei, G. Martinska, J. Messchendorp, A. Micherdzinska, A. Nogga, N. Piskunov, D. Protic, A. Ramazani, P. Von Rossen, BJ. Roy, H. Sakai, PU. Sauer, K. Sekiguchi, I. Sitnik, R. Siudak, R. Skibiński, R. Sworst, J. Urban, H. Witała, J. Zejma, W. Zipper
abstract
A large set of high precision cross sections, vector A(x), A(y) and tensor A(xx), A(xy), A(yy) analyzing powers for the (1)H((d) over right arrow ,pp)n breakup reaction were measured at 130 MeV beam energy with the detection system covering a large part of the phase space. Results are compared with rigorous theoretical calculations employing various models of the three-nucleon system dynamics. The cross section data allowed to establish evidence for three-nucleon force contributions and to confirm predictions of sizable effect of the Coulomb force in the breakup reaction. Analyzing power data are generally quite well described by theoretical predictions even with pure NN interactions. However, in some regions discrepancies has been observed for tensor analyzing powers, only rarely cured by inclusion of the three nucleon force. This indicates incompletness of the present-day treatment of the spin part of three nucleon system dynamics.
Search for eta-mesic nuclei in a recoil-free transfer reaction
A. Budzanowski, A. Chatterjee, P. Hawranek, R. Jahn, BK. Jain, V. Jha, S. Kailas, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, M. Lesiak, J. Lieb, LC. Liu, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, P. Shukla, I. Sitnik, R. Siudak, R. Tsenov, J. Urban, G. Vankova
abstract
We have studied the reaction p + Al-27 -> He-3 + p + pi(-) + X at recoil-free kinematics. An eta meson possibly produced in this reaction would be thus almost at rest in the laboratory system and could therefore be bound with high probability, if nuclear eta states exist. The decay of such a state through the N*(1535) resonance would lead to a proton-pi(-) pair emitted in opposite directions. For these conditions we find some indication of such a bound state. An upper limit of approximate to 0.5 nb is found.
A threshold Cherenkov detector for K+/pi(+) separation using silica aerogel
R. Siudak, A. Budzanowski, A. Chatterjee, H. Clement, E. Dorochkevitsch, J. Ernst, P. Hawranek, F. Hinterberger, R. Jahn, L. Jarczyk, R. Joosten, K. Kilian, D. Kirillov, S. Kliczewski, D. Kolev, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, F. Massmann, J. Munkel, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, B. Roy, I. Sitnik, I. Slepnev, J. Smyrski, R. Tsenov, K. Ulbrich, J. Urban, G. Vankova, GJ. Wagnerj, R. Ziegler
abstract
A new threshold Cherenkov detector has been built for the detection of charged pions in the focal plane of a magnetic spectrograph. Silica aerogel with refractive index of n = 1.05 is applied as a radiator. The detector exhibits a very high detection efficiency for pions with momenta >= 900MeV/c. Using two Cherenkov detectors in series a very high pion suppression factor of 10(5) was achieved. (C) 2008 Elsevier B.V. All rights reserved.
Competition of coalescence and "fireball" processes in nonequilibrium emission of light charged particles from p+Au collisions
A. Budzanowski, M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of the double differential cross sections d(2)sigma/d Omega dE were measured for p, d, t,He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11,B-12 isotopes produced in reactions of 1.2- and 1.9-GeV protons on a Au target. The beam energy dependence of the data, supplemented by the cross sections from a previous experiment at 2.5 GeV, is very smooth. The shape of the spectra and angular distributions do not change significantly in the beam energy range from 1.2 to 2.5 GeV. However, the absolute value of the cross sections increases for all ejectiles. The intermediate mass fragment spectra and their angular distributions are very well reproduced by a phenomenological model of two emitting, moving sources, with parameters smoothly varying with energy. The double differential cross sections for light charged particles were analyzed in the framework of the microscopic model calculations of intranuclear cascade, including the coalescence of nucleons and a statistical model for evaporation of particles from excited residual nuclei. However, the energy and angular dependencies of the data agree with neither predictions of the microscopic intranuclear cascade calculations for protons nor the coalescence calculations for other light charged particles. A very good description of the data is achieved by the phenomenological inclusion of the emission of light charged particles from a "fireball" (i.e., a fast and hot moving source). It was found that the nonequilibrium processes are very important for the production of light charged particles. They exhaust 40%-80% of the total cross section-depending on the emitted particles. Coalescence and fireball emission yield comparable contributions to the cross sections with the exception of the He-3 data where coalescence clearly dominates. For all light charged particles, the ratio of nonequilibrium processes to processes proceeding through a phase of statistical equilibrium does not change significantly between the beam energies of 1.2 and 2.5 GeV.
A large acceptance scintillator detector with wavelength shifting fibre readout for search of eta-nucleus bound states
MG. Betigeri, PK. Biswas, A. Budzanowski, A. Chatterjee, R. Jahn, S. Guha, P. Hawranek, BK. Jain, SB. Jawale, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, T. Kutsarova, M. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Prasuhn, D. Protic, J. Ritman, P. von Rossen, BJ. Roy, P. Shukla, I. Sitnlk, R. Sludak, R. Tsenov, M. Ulicny, J. Urban, G. Vankova
abstract
A large acceptance scintillator detector with wavelength shifting optical fibre readout has been designed and built to detect the decay particles of eta-nucleus bound system (the so-called eta-mesic nuclei), namely, protons and pions. The detector, named as ENSTAR detector, consists of 122 pieces of plastic scintillator of various shapes and sizes, which are arranged in a cylindrical geometry to provide particle identification, energy loss and coarse position information for these particles. A solid angle coverage of similar to 95% of total 4 pi is obtained in the present design of the detector. Monte Carlo phase space calculations performed to simulate the formation and decay of eta-mesic nuclei suggest that its decay particles, the protons and pions are emitted with an opening angle of 150 +/- 20 degrees, and with energies in the range of 25-300 and 225-450 MeV, respectively. The detailed GEANT simulations show that similar to 80% of the decay particles (protons and pions) can be detected within ENSTAR. Several test measurements using alpha source, cosmic-ray muons, etc. have been carried out to study the response of ENSTAR scintillator pieces. The in-beam tests of fully assembled detector with proton beam of momentum 870 MeV/c from the Cooler synchrotron COSY have been performed. The test results show that the scintillator fibre design chosen for the detector.
Non-equilibrium emission of complex fragments from p plus Au collisions at 2.5 GeV proton beam energy
A. Bubak, A. Budzanowski, D. Filges, F. Goldenbaum, A. Heczko, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, W. Migdal, N. Paul, B. Piskor-Ignatowicz, M. Puchala, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski, P. Wustner
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE was measured for reactions induced by 2.5 GeV protons on Au target with isotopic identification of light products (H, He, Li, Be, and B) and with elemental identification of heavier intermediate mass fragments (C, N, O, F, Ne, Na, Mg, and Al). It was found that two different reaction mechanisms give comparable contributions to the cross sections. The intranuclear cascade of nucleon-nucleon collisions followed by evaporation from an equilibrated residuum describes the low energy part of the energy distributions whereas another reaction mechanism is responsible for the high energy part of the spectra of composite particles. A phenomenological model description of the differential cross sections by isotropic emission from two moving sources led to a very good description of all measured data. Values of the extracted parameters of the emitting sources are compatible with the hypothesis claiming that high energy particles emerge from preequilibrium processes consisting in a breakup of the target into three groups of nucleons; small, fast, and hot fireball of similar to 8 nucleons, and two larger, excited prefragments, which emit light charged particles and intermediate mass fragments. The smaller of them contains similar to 20 nucleons and moves with a velocity larger than the CM velocity of the proton projectile and the target. The heavier prefragment behaves similarly as the heavy residuum of the intranuclear cascade of nucleon-nucleon collisions.
Study of the eta meson production in the (d)over-right-arrow + d ->(4)he + eta reaction using the polarized beam
M. Lesiak, M. Abdel-Bary, A. Budzanowski, A. Chatterjee, J. Ernst, P. Hawranek, R. Jahn, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Prasuhn, D. Protic, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, R. Tsenov, M. Ulicny, J. Urban, G. Vankova, C. Wilkin
abstract
The measurement of the. meson production in (d) over right arrow + d -> He-4 + eta reaction has been performed at the Big Karl magnetic spectograph at COSY synchrotron in Julich. The vector and tensor polarized deuetron beam at the excess energy of Q=16 MeV was used. The preliminary results for the unpolarized cross section are presented here.
Search for eta-nucleus bound state at cosy
V. Jha, A. Budzanowski, A. Chatterjee, J. Ernst, P. Hawranek, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, T. Kutsarova, M. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, J. Niskanenn, N. Piskunov, D. Prasuhn, D. Protic, P. von Rossen, BJ. Roy, P. Shukla, I. Sitnik, R. Siudak, R. Tsenov, M. Ulicny, J. Urban, G. Vankova
abstract
An experiment to search for the bound state of eta meson in nuclei has been performed at COSY, Juelich using the ENSTAR detector and Big Karl magnetic spectrometer. Reaction (p,He-3) on Al-27 target has been used to search for the eta-mesic nucleus Mg-25 eta in the missing mass distribution from the measured 3He particles. A preliminary figure of 1.5 nb for the upper limit of the formation cross section of eta-nucleus bound state has been determined.
Experimental study of the pd -> He-3 K+K- and pd -> He-3 phi reactions close to threshold
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, R. Joosten, K. Kilian, A. Kozela, H. Machner, A. Magiera, J. Munkel, P. von Neumann-Cosel, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, R. Tolle, C. Wilkin
abstract
Two-kaon production in proton-deuteron collisions has been studied at three energies close to threshold using a calibrated magnetic spectrograph to measure the final He-3 and a vertex detector to measure the K+K- pair. Differential and total cross sections are presented for the production of phi-mesons, decaying through phi -> K+K-, as well as for prompt K+K- production. The prompt production seems to follow phase space in both its differential distributions and in its energy dependence. The amplitude for the pd -> He-3 phi reaction varies little for excess energies below 22 MeV and the value is consistent with that obtained from a threshold measurement. The angular distribution of the K+K- decay pair shows that near threshold the phi-mesons are dominantly produced with polarization m=0 along the initial proton direction. No conclusive evidence for f(0)(980) production is found in the data.
Light charged particle and intermediate mass fragment cross-sections in GeV proton-induced reactions
V. Bollini, A. Bubak, A. Budzanowski, J. Cugnon, D. Filges, F. Goldenbaum, A. Heczko, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, P. Kulessa, H. Machner, A. Magiera, W. Migdal, K. Nunighoff, N. Paul, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski, E. Kozik
abstract
As an international collaboration PISA (Proton Induced SpAllation) has initiated measurements of total and double differential cross-sections for products of spallation reactions at the proton accelerator COSY in Julich (Germany) in order to study secondary particle production created in structural, window, and target materials by proton beams up to 2.5 GeV incident kinetic energy. In the framework of Spallation Neutron Sources and accelerator-driven systems, residual nuclei (H, He up to intermediate mass fragrments) production cross-sections are of great importance for estimation of damage in target and structural materials. Reliable and comprehensive experimental data, especially for p-energies beyond I GeV will serve as benchmarks for code development and validation. Data taken by Bragg curve spectroscopy and silicon detector telescopes for the reaction 1.9 GeV p + Ni(Au) will be discussed and kinetic energy spectra of light ions and intermediate mass fragments will be presented. (c) 2006 Elsevier B.V. All rights reserved.
The eta meson physics program at GEM
H. Machner, M. Abdel-Bary, A. Budzanowski, A. Chatterjee, J. Ernst, P. Hawranek, R. Jahn, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kirillov, D. Kolev, M. Kravcikova, T. Kutsarova, M. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Prasuhn, D. Protic, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, R. Tsenov, M. Ulicny, J. Urban, G. Vankova, C. Wilkin
abstract
Some experimental studies of eta production and eta interactions performed or presently under way by the GEM collaboration at COSY Julich are reviewed.
Near-threshold eta-meson production in the dd -> He-4 eta reaction
A. Wronska, V. Hejny, C. Wilkin, S. Dymov, C. Hanhart, V. Komarov, HR. Koch, A. Kulikov, A. Magiera, T. Mersmann, S. Mikirtytchiants, H. Ohm, D. Prasuhn, R. Schleichert, H. Stein, H. Stroher
abstract
The dd -> He-4 eta reaction has been investigated near threshold using the ANKE facility at COSY-Julich. Both total and differential cross-sections have been measured at two excess energies, Q = 2.6 MeV and 7.7 MeV, with a subthreshold measurement being undertaken at Q = - 2.6 MeV to study the physical background. While consistent with isotropy at the lower energy, the angular distribution reveals a pronounced anisotropy at the higher one, indicating the presence of higher partial waves. Options for the decomposition into partial amplitudes and their consequences for the determination of the s-wave eta alpha scattering length are discussed.
A precision determination of the mass of the eta meson
M. Abdel-Bary, A. Budzanowski, A. Chatterjee, J. Ernst, P. Hawranek, R. Jahn, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kolev, M. Kravcikova, T. Kutsarova, A. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, N. Piskunov, D. Prasuhn, D. Protic, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, M. Smiechowicz, HJ. Stein, R. Tsenov, M. Ulicny, J. Urban, G. Vankova, C. Wilkin
abstract
Several processes of meson production in proton-deuteron collisions have been measured simultaneously using a calibrated magnetic spectrograph. Among these processes, the eta meson is seen clearly as a sharp missing-mass peak on a slowly varying background in the p + d -> He-3 + X reaction. Knowing the kinematics of the other reactions with well determined masses, it is possible to deduce a precise mass for the eta meson. The final result, m(eta) = 547.311 +/- 0.028(stat) 0.032(syst) MeV/c(2), is significantly lower than that found by the recent NA48 measurement, though it is consistent with values obtained in earlier counter experiments. (c) 2005 Elsevier B.V. All rights reserved.
Detailed comparison of the pp ->pi(+) pn and pp ->pi+ d reactions at 951 MeV
M. Abdel-Bary, A. Budzanowski, A. Chatterjee, J. Ernst, P. Hawranek, F. Hinterberger, V. Jha, K. Kilian, S. Kliczewski, D. Kirillov, D. Kolev, M. Kravcikova, T. Kutsarova, A. Lesiak, J. Lieb, H. Machner, A. Magiera, R. Maier, G. Martinska, S. Nedev, J. Niskanen, N. Piskunov, D. Prasuhn, D. Protic, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, A. Smiechowicz, R. Tsenov, M. Ulicny, J. Urban, G. Vankova, C. Wilkin
abstract
The positively charged pions produced in proton-proton collisions at a beam momentum of 1640 MeV/c were measured in the forward direction with a high resolution magnetic spectrograph. The missing mass distribution shows the bound state (deuteron) clearly separated from the pn continuum. Despite the very good resolution, there is no evidence for any significant production of the pn system in the spin-singlet state. However, the sigma (pp -> pi(+)pn)/sigma(pp -> pi(+)d) cross section ratio is about twice as large as that predicted from S-wave final-state-interaction theory and it is suggested that this is due to D-state effects in the pn system. (c) 2005 Published by Elsevier B.V.
PISA - an experiment for fragment spectroscopy at the Internal Beam of COSY: application of an Axial Ionization Chamber
R. Barna, V. Bollini, A. Bubak, A. Budzanowski, D. De Pasquale, D. Filges, SV. Fortsch, F. Goldenbaum, A. Heczko, H. Hodde, A. Italiano, L. Jarczyk, B. Kamys, J. Kisiel, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, P. Kulessa, H. Machner, A. Magiera, J. Majewski, W. Migdal, H. Ohm, N. Paul, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, H. Schaal, R. Siudak, E. Stephan, GF. Steyn, R. Sworst, T. Thovhogi, M. Wojciechowski, W. Zipper
abstract
The Proton-Induced SpAllation (PISA) experiment performed at the internal beam facility of the COSY storage ring in Julich, Germany, which is aimed at the precise measurement of double differential cross-sections over a broad range of energies and angles for spallation reactions induced by protons of 200-2500 MeV energy in various targets, is presented. In this paper the emphasis is put on the design, principles of operation and performance of a Bragg Curve Detector (BCD) optimized for internal beam experiments at storage rings. Very clean and distinct product identification (with Z up to similar to 14) from reactions, in which a Ni target was bombarded with a 1.9 GeV circulating proton beam, is obtained. The individual elements are resolved for emission energies higher than 0.5 MeV/nucleon. Moreover, due to the detector readout achieved by coupling a specially designed current sensitive preamplifier directly to a sampling ADC, the shape analysis of the signals from the BCD allows the isotope identification of light particles with A up to similar to 11. It is also found that the BCD can be used efficiently as a thin DeltaE detector for the telescope consisting of the BCD and a series of silicon detectors. (C) 2003 Elsevier B.V. All rights reserved.
Isospin symmetry breaking as a tool for particle physics investigations
A. Magiera, S. Abdel-Bary, P. Hawranek, J. Ilieva, K. Kilian, D. Kirilov, S. Kistryn, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, G. Martinska, L. Pentchev, N. Piskunov, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, J. Smyrski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
The importance of the isospin symmetry breaking in extracting various particle physics parameters is discussed. In particular the measurement of isospin symmetry breaking in the reaction pd --> (3)Hpi(+)/(3)Hepi(0) is presented. The energy dependence of the measured cross sections ratio indicate isospin symmetry breaking effects. Within a simple model based on pi(0) - eta meson mixing the mixing angle of these mesons is extracted.
Study of p+d ->(3)A+pi reactions in the Delta-resonance region
S. Abdel-Samad, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, D. Frekers, P. Hawranek, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikovaa, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, H. Nann, L. Pentchev, D. Protic, P. von Rossen, BJ. Roy, R. Siudak, A. Strzalkowski, R. Tsenov, M. Ulicny, J. Urban, K. Zwoll
abstract
A stack of annular detectors made of high-purity germanium was used to measure p + d --> He-3+ pi(0) and p + d --> H-3 + pi(+) differential and total cross-sections at beam momenta from 900 MeV/c to 1050 MeV/c. The total cross-sections are consistent with Delta-excitation. The differential data consist of two components. One corresponds to large momentum transfer from the projectile to the pion, the other to small momentum transfer. The former shows an independence of the slope as a function of the momentum transfer t (scaling). The scale parameter is different for pi(+) and pi(0) emission which violates isospin symmetry. The second component which is almost isotropic is in agreement with isospin symmetry. It is approximately a quarter of the total yield in the Delta-resonance region.
pi(0)-eta meson mixing in pd -> H-3 pi(+)/He-3 pi(0) reactions
M. Abdel-Bary, P. Hawranek, J. Ilieva, K. Kilian, D. Kirilov, S. Kistryn, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, L. Pentchev, N. Piskunov, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, J. Smyrski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
Beam momentum dependence of the experimental cross sections for pd-->(3)Hpi(+)/(3)Hepi(0) reactions have been studied at large proton-pion relative angle. The measurements were performed for five beam momenta in the region of the eta meson production threshold. Observed behavior of the measured cross sections ratio reveals manifestations of the isospin symmetry breaking effects. A simple model allows one to interpret the isospin symmetry breaking in terms of pi(0)-eta meson mixing. Based on that model analysis of the experimental results leads to the mixing angle value of 0.006+/-0.005 rad.
Isospin symmetry breaking and scaling observed in pion production in p+d reactions
S. Abdel-Samad, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, D. Frekers, P. Hawranek, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, H. Nann, L. Pentchev, D. Protic, P. von Rossen, BJ. Roy, R. Siudak, A. Strzalkowski, R. Tsenov, M. Ulicny, J. Urban, K. Zwoll
abstract
A stack of annular detectors made of high purity germanium was used to measure p+d --> He-3+pi(0) and p+d --> H-3+pi(+) differential and total cross sections at beam momenta from 900 to 1050 MeV/c. The total cross sections are consistent with Delta-excitation. The differential data consist of two components. One corresponds to large momentum transfer from the projectile to the pion, the other to small momentum transfer. The former shows an independence of the slope as function of the momentum transfer t (scaling). The scale parameter is different for pi(+) and pi(0) emission which violates isospin symmetry. The second component which is almost isotropic is in agreement with isospin symmetry. It is approximately a quarter of the total yield in the Delta resonance region. (C) 2002 Elsevier Science B.V. All rights reserved.
Isospin symmetry breaking: Experimental observation
J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, P. Hawranek, J. Ilieva, L. Jarczyk, V. Jha, K. Kilian, D. Kirillov, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, H. Nann, L. Pentchev, N. Piskunov, D. Protic, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, A. Strzalkowski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
Experiments have been performed at COSY, Juelich to investigate isospin symmetry breaking effects in nuclear reactions by studying simultaneously the two reactions p + d --> H-3+pi(+) and P + d --> He-3+pi(0) at beam energies close to corresponding eta production threshold. The beam momentum dependence of the ratio of cross section of these two reactions would be indicative of isospin symmetry breaking, if any. The present measurement reports observation of isospin symmetry breaking effect. The results are presented.
Simultaneous measurements of p+d -> He-3+pi(0) and p+d -> H-3 +pi(+) reactions with the GEM detector
S. Abdel-Samad, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, D. Frekers, P. Hawranek, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, H. Nann, L. Pentchev, D. Protic, P. von Rossen, BJ. Roy, R. Siudak, M. Ulicny, A. Strzakowski, R. Tsenov, J. Urban, K. Zwoll
abstract
A stack of annular detectors made of high purity germanium was used to measure p + d --> (3) He + pi(0) and p + d --> (3) H + pi(+) differential and total cross sections at beam momenta from 750 MeV/c to 1050 MeV/c. The total cross sections are consistent with A-excitation. The differential data consist of two components. One corresponds to large momentum transfer from the projectile to the pion, the other to small momentum transfer. The former shows an independence of the slope as function of the momentum transfer t (scaling). The scale parameter is different for pi(+) and pi(0) emission which violates isospin symmetry. The second component which is almost isotropic is in agreement with isospin symmetry. It is approximately a quarter of the total yield in the Delta resonance region.
Magnetic spectrometer Big Karl for studies of meson production reactions
J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, P. Hawranek, J. Ilieva, L. Jarczyk, K. Kilian, S. Kistryn, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, L. Pentchev, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
The paper describes modifications of the Julich magnetic spectrometer Big Karl needed to study meson production and especially to investigate charge symmetry breaking effects-an experiment that requires a high-precision measurement. New elements that have been added to Big Karl have extended the spectrometer capabilities to a much wider momentum range. The new features also facilitate simultaneous detection of particles with very different rigidities. The experimental methods for improving background and determining relative acceptance of the spectrometer at various rigidities are presented. (C) 2001 Elsevier Science B.V. All rights reserved.
Development of a compact photon detector for ANKE at Cosy
V. Hejny, J. Bacelar, V. Chernyshev, M. Buscher, M. Hoek, HR. Koch, H. Lohner, H. Machner, A. Magiera, R. Novotny, K. Romer, H. Stroher, A. Wronska
abstract
Recent improvements in the performance of PbWO4, a high-density inorganic scintillator, offer the possibility to design very compact, large-acceptance electromagnetic calorimeters with excellent timing and good energy resolution, applicable also for photon energies below 1 Gev. Such a detection system is planned to be built for the internal magnetic spectrometer ANKE (Apparatus for Studies of Nucleon and Kaon Ejectiles) at the Cooler Synchrotron (Cosy) Julich. The limited space and stray magnetic fields of ANKE place severe boundary conditions, which have to be taken into account for detector layout and the choice of photo sensors. (C) 2002 Elsevier Science B.V. All rights reserved.
Measurement of the pp -> pp pi(0) reaction at 850 MeV/c and partial wave cross sections
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, R. Maier, H. Nann, J. Niskanen, D. Prasuhn, L. Pentchev, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
A stack of annular detectors made of high purity germanium was used to measure pp-->pppi(0) differential cross sections at a beam momentum of 850 MeV/c. A total cross section of sigma=9.1+/-1.1 mub is deduced. The fitted distribution of different partial waves to the world total cross section data and to the present differential cross sections favors an approach without low-energy approximations, with the standard value for the final state interaction scattering length, and an important contribution from an intermediate NDelta state.
Development of a compact photon detector for ANKE at COSY Julich
M. Buscher, V. Hejny, HR. Koch, H. Machner, H. Seyfarth, H. Stroher, M. Hoek, R. Novotny, K. Romer, J. Bacelar, H. Lohner, A. Magiera, A. Wronska, V. Chernychov
abstract
COSY Hilich is a race-track shaped synchrotron which accelerates and cools beams of protons (both polarized and unpolarized) and deuterons with momenta up to 3.6 GeV/c. Those beams are delivered to internal and external target positions for hadron physics experiments. Since magnetic and time-of-flight detectors based on organic scintillators are used in the experimental setups, all measurements are essentially "photon blind". Recent improvements in the performance of high-density inorganic scintillators offer the possibility to design very compact large-acceptance electromagnetic calorimeters with excellent timing and good energy resolution, applicable also for photon energies below 1 GeV. Such a detection system, based on PbWO4, is planned to be built for the internal magnetic spectrometer ANKE at COSY Julich. The limited space and stray magnetic fields of ANKE place severe boundary conditions, which have to be taken into account for detector layout and the choice of photo sensors.
Simultaneous measurements of the p+d -> (A=3)+pi reactions
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, RV. Srikantiah, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
A stack of annular detectors made of high-purity germanium was used to measure simultaneously pd --> H-3 pi (+) and pd --> He-3 pi (0) differential cross sections at beam momenta of 750 MeV/c, 800 MeV/c, and 850 MeV/c over a large angular range. The extracted total cross sections for the pd --> He-3 pi (0) reactions bridge a gap between near threshold data and those in the resonance region. The ratio of the cross sections for the two reaction channels taken at the same eta = P-pi(cm) / m(pi) yields 2.11 +/- 0.08 indicating that a deviation from isospin symmetry is very small. (C) 2001 Elsevier Science B,V. All rights reserved.
Meson production in p+d reactions
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
Total and differential cross sections for the reactions pd --> (3)Hcm(0) with m = pi, eta were measured with the GEM detector at COSY at momenta between threshold and the maximum of the corresponding nucleon resonance. For both reactions a strong forward-backward asymmetry was found. The data were compared with model calculations.
Differential cross sections measurement for the pp -> d pi(+) reaction at 850 MeV/c
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
A stack of annular detectors made of high purity germanium and a magnet spectrograph were used to measure pp-->d pi (+) differential cross sections at a beam momentum of 850 MeV/c over a large angular range. A total cross section of sigma = 0.2301+/-0.0036(stat)+/-0.0230(syst) mb and an anisotropy A(2)/A(0) = 0.856+/-0.016 were deduced. These values follow fits to low energy data. From the present A(2) value it is found that the pionic p-wave amplitude a(0) is larger than assumed so far.
Charge and isospin symmetry breaking via external pi(0)-eta meson mixing
A. Magiera, H. Machner
abstract
A simple model of isospin and charge symmetry breaking due to external pi(0)-eta meson mixing is presented. It is based on amplitudes extracted from the available experimental data for pd --> He-3 pi(0), pd --> He-3 eta and dd --> He-4 eta reactions. Predictions of the strength of isospin symmetry breaking in pd --> H-3 pi(+)/He-3 pi(0) reactions are given. Within the same model, the cross section for the charge symmetry breaking dd --> He-4 pi(0) reaction is calculated. (C) 2000 Elsevier Science B.V. All rights reserved.
Test of charge independence in p+d ->(A=3)+pion reactions
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
A stack of annular detectors made of high purity germanium was used to measure pd --> H-3 pi(+) and pd --> He-3 pi(0) differential cross sections simultaneously at 850 MeV/c over a large angular range. The ratios of the cross sections and for averaged squared matrix elements is constant for large momentum transfer. The mean values are 2.27 +/- 0.05 and 2.23 +/- 0.07, respectively.
Measurement of pd -> He-3 eta in the S-11 resonance
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, S. Igel, J. Ilieva, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, G. Lippert, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BR. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
We have measured the reaction pd --> He-3 eta at a proton beam energy of 980 MeV, which is 88.5 MeV above threshold using the new 'germanium wall' detector system. A missing-mass resolution of the detector system of 2.6% was achieved. The angular distribution of the meson is forward peaked. We found a total cross section of (573 +/- 83 (stat.) +/- 69 (syst.)) nb. The excitation function for the present reaction is described by a Breit Wigner form with parameters from photoproduction. (C) 2000 Published by Elsevier Science B.V. All rights reserved.
Meson production in p + d reactions
W. Klimala, M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, B. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
Differential cross sections of the pd --> H-3 pi (+) /He-3 pi (0) reactions were measured simultaneously at three beam momenta: 750 MeV/c, 800 MeV/c and 850 MeV/c. The differential cross section of the pd --> He-3 eta was measured at 1675 MeV/c beam momentum. All measurements cover a wide angular range in the CM system. The experiments were performed at the COSY accelerator in Julich, Germany, by means of high purity Germanium Wall detector together with the magnetic spectrometer BIG KARL. Estimated cross sections were compared with the predictions of simple theoretical models. In case of isospin symmetric pd --> H-3 pi (+) /He-3 pi (0) reactions, the average cross section ratio was estimated.
Near threshold two meson production with the pd -> He-3 pi(+)pi(-) and pd -> (HeK+K-)-He-3 reactions
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. von Neumann-Cosel, D. Rosendaal, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, C. Wilkin
abstract
Wear threshold two meson production via the reactions pd --> He-3 pi(+)pi(-) and pd --> He-3 K+K- was measured kinematically complete with the MOMO experiment at COSY. The obtained two pion invariant mass spectra and angular distributions depict a remarkable deviation from phase space. The two kaon data are consistent with phase space topped by a clear signal of the phi meson.
Meson production in p+d reactions
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, RV. Srikantiah, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
Pion and sl production on the deuteron are studied at energies in the vicinity of the absolute threshold. The data are expected to be sensitive to high momentum components in the deuteron wavefunction as well as to two step processes.
Pion-pion p-wave dominance in the pd -> He-3 pi(+)pi(-) reaction near threshold
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. von Neumann-Cosel, D. Rosendaal, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, C. Wilkin
abstract
The cross section for the pd-->He-3 pi(+)pi(-) reaction has been measured in a kinematically complete experiment at a c.m. excess energy of Q = 70 MeV. The striking energy and angular distributions are reproduced in a simple model calculation when it is assumed that the reaction is dominated by p-wave pi(+)pi(-) pairs. This is in complete contrast to the results of inclusive measurements at somewhat higher beam energies which show a strong s-wave ABC enhancement at low pi pi masses. [S0556-2813(99)51111-4].
The germanium wall of the GEM detector system
M. Betigeri, E. Bialkowski, H. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernste, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, S. Igel, J. Ilieva, L. Jarczyk, M. Jochmann, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, G. Lippert, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, RV. Srikantiah, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
A stack of annular detectors made of high-purity germanium was developed. The detectors are position sensitive with radial structures. The first one ("Quirl") is double-sided position sensitive defining 40 000 pixels, the following three (E1, E2 and E3) have 32 wedges each. The Quirl acts as tracker while the other three act as calorimeter. The stack was successfully operated in meson production reactions close to threshold. (C) 1999 Elsevier Science B.V. All rights reserved.
Hydrostatic high pressure studies of polymer thick-film resistors
A. Dziedzic, A. Magiera, R. Winsiewski
abstract
The behaviour of carbon black/polyesterimide thick-film resistors under high hydrostatic pressure (up to 5000 bar) and at the temperature range from 20 to 150 degrees C is presented. The gradual resistance decrease observed with pressure increase is dependent on carbon black kind and contents. Much higher compressibility of polymer matrix than active phase affects gradual increase of carbon black volume fraction. The basic relationship of percolation theory, rho proportional to(nu(CB)-nu(CB))(-t), is used successfully for semi-quantitative analysis of high pressure effect on tested devices. It is shown that this effect is temperature independent. (C) 1998 Elsevier Science Ltd. All rights reserved.
Meson production studied with the GEM detector
W. Garske, MG. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, K. Grewer, A. Hamacher, S. Igel, I. Ilieva, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, BJ. Lieb, G. Lippert, H. Machner, A. Magiera, R. Maier, H. Nann, E. Pentchev, HS. Plendl, D. Prasuhn, D. Protic, B. Razen, P. von Rossen, B. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
Measurements of proton induced meson production on hydrogen and deuterium targets using the GEM-detector at COSY are described. Preliminary estimates of the total cross section are presented. Results of the pp --> d pi(+) and pp --> pp pi(o) cross section are in agreement with previous findings. The total cross section of pd --> He-3 pi(o) is consistent with results from pion absorption but a surprisingly large value was found at a beam momentum of 750 MeV/c. The reaction pd --> He-3 eta was measured at two beam energies and was identified by missing mass technique.
Beam energy calibration with meson production
B. Razen, MG. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, M. Hawash, S. Igel, I. Ilieva, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, BJ. Lieb, G. Lippert, H. Machner, A. Magiera, R. Maier, H. Nann, HS. Plendl, D. Protic, P. von Rossen, B. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
The magnetic spectrometer BIG KARL is used to get energy calibration fix-points for the external beam of COSY-Julich. These fixpoints were obtained by measuring the meson-production reaction pp --> d pi(+) close to threshold and at the beam momentum, where the forward pions and the backward deuterons have the same momentum.
Exclusive near threshold two-pion production with the MOMO experiment at COSY
S. Bavink, F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. vonNeumann-Cosel, D. Rosendaal, PV. Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, R. Wurzinger
abstract
Near threshold two pion production via the reaction pd --> (HE)-H-3 pi(+)pi(-) was measured kinematically complete with the MOMO experiment at COSY. ii remarkable deviation of thr obtained two pion invariant mass spectra from phase space as well as a predominant back to back and sidewise emission of the two pions was observed.
Sequential reaction processes in the C-12+C-12 system at an energy of 28.7 MeV/nucleon
A. Magiera, J. Hebenstreit, L. Jarczyk, B. Kamys, A. Strzalkowski, B. Styczen, W. Oelert, P. von Rossen, H. Seyfarth
abstract
Inclusive spectra of different ejectiles and coincidence spectra of alpha particles with various nuclides emerging from the collisions of C-12 ions Of energy 344.5 MeV with a C-12 target have been measured. A large fraction of the observed cross section is contained in the continuous part of the inclusive spectra. In the coincidence data the excitation of states of intermediate nuclei is observed which indicates the sequential mechanism of the reaction. Calculations performed with a simple phenomenological model of such processes reproduce well the shape and magnitude of both inclusive and coincidence spectra. The contribution of various reaction mechanisms to the total reaction cross section is estimated.
High pressure effect on polymer thick-film resistors
A. Dziedzic, A. Magiera, R. Wisniewski
abstract
This paper presents behaviour of model polymer thick-film resistors under high hydrostatic pressure (up to 5000 bar) at the temperature range from 20 to 150 degrees C. The resistance decreases gradually with pressure increase The relative resistance changes are not temperature-dependent. The semi-quantitative explanation of observed results is presented based on percolation theory.
Exclusive near threshold two-pion production with the MOMO experiment at COSY
S. Bavink, F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. von Neumann-Cosel, D. Rosendaal, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, R. Wurzinger
abstract
Near threshold two pion production via the reaction pd --> He-3 pi(+)pi(-) was measured kinematically complete with the MOMO experiment at COSY. A remarkable deviation of the obtained two pion invariant mass spectra from phase space as well as a predominat sidewise and back to back emission of the two mesons was observed.
Two-pion production at MOMO
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, R. Frascaria, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, U. Kuhn, H. Machner, A. Magiera, R. Maschuw, T. MayerKuckuk, G. Mertler, B. Metsch, J. Munkel, P. vonNeumannCosel, T. vonOepen, HR. Petry, D. Rosendaal, P. vonRossen, K. Scho, F. SChwandt, R. Siebert, J. Smyrski, A. Strzalkowski, R. Tolle, R. Wurzinger, R. Ziegler
abstract
The reaction pd-->He-3 pi(+)pi(-) was measured at 1150 MeV/c proton beam momentum using MOMO instalation at COSY.
Limitation of the fusion cross section for the C-12+B-11 system at E(cm)=36.5 and 41.7 MeV
M. Kistryn, L. Jarczyk, B. Kamys, A. Magiera, Z. Rudy, A. Strzalkowski, R. Barna, V. DAmico, D. dePasquale, A. Italiano, M. Licandro
abstract
Inclusive spectra of protons, alpha particles, and heavy ejectiles as well as coincidence spectra of protons and ru particles with heavy ejectiles were measured for C-12 + B-11 system at several angles and at two laborabory energies of B-11: 70 and 80 MeV. A Hauser-Feshbach model analysis was performed for inclusive and coincidence spectra to extract the fusion cross section values 800 +/- 50 mb and 750 +/- 50 mb at E(lab) 70 and 80 MeV, respectively. These values are in agreement with the limitation of the fusion imposed by entrance channel conditions and by properties of the compound nucleus, in contradiction to results of earlier investigations which suggested an anomalous energy dependence of the fusion.
Five-nucleon simultaneous and sequential transfer in the C-12(B-11, Li-6) O-17 and C-12(d,Li-7)Be-7 reactions
L. Jarczyk, B. Kamys, M. Kistryn, A. Magiera, Z. Rudy, A. Strzalkowski, R. Barna, V. DAmico, D. DePasquale, A. Italiano, M. Licandro
abstract
Measurements of the angular distributions of the C-12(B-11,Li-6)O-17 reaction were performed at three energies of a B-11 beam: 25, 35, and 40 MeV. The results were analyzed in the frame of the exact finite range distorted wave Born approximation of the first and the second order assuming the simultaneous and sequential transfer of the neutron and the alpha particle. Such an analysis was also performed for previously measured angular distributions of the C-12(d,Li-7)Be-7 reaction at E(lab) = 78 MeV. In both reactions under investigation dominance was found of the simultaneous transfer of the a particle and the nucleon correlated to the: He-5(Li-5) cluster in the ground or the first excited state.
