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1. Stopping and radial flow in central58Ni+58Nicollisions between1Aand2AGeV

Author

C. Roy, J. Mösner, D. Wohlfarth, A. Genoux-Lubain, Vladislav Manko, C. Pinkenburg, A. Buta, Christian Claude Kuhn, G. Guillaume, Byung-Sik Hong, E. Häfele, James Ritman, B. Sikora, D. Best, W. Reisdorf, F. Jundt, V. Simion, P. Crochet, W. Neubert, S. Mohren, Mihai Petrovici, U. Sodan, Peter Wagner, J. Biegansky, B. de Schauenburg, A. Somov, Y. Leifels, A. Lebedev, T. Wienold, C. Maazouzi, V. Amouroux, Vasilev, A. Zhilin, R. Kotte, I. Belyaev, Fouad Rami, G.S. Wang, D. Pelte, L. Fraysse, Z. Seres, N. Herrmann, K. D. Hildenbrand, M. Eskef, J. P. Coffin, J. Kecskemeti, J. P. Alard, Pascal Dupieux, D. Schüll, P. Fintz, I. Legrand, M. Trzaska, M. Kirejczyk, L. Tizniti, G. Berek, K. Siwek-Wilczyńska, Nicole Bastid, G. Goebels, R. Dona, P. Pras, M. Korolija, Z. Fodor, and A. Gobbi

Subjects
Physics, Nuclear and High Energy Physics, Energy loss, 010308 nuclear & particles physics, Nuclear Theory, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, Quantum molecular dynamics, Nuclear physics, Nickel, chemistry, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Radial flow, Nuclear Experiment, 010306 general physics
Published
1998
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2. Out-of-plane emission of nuclear matter in Au+Au collisions between 100 and 800 AMeV

Author

D. Best, L. Fraysse, D. Wohlfarth, W. Neubert, U. Sodan, J. P. Wessels, M. Trzaska, N. Cindro, N. Herrmann, Z. Basrak, P. Fintz, C. Maazouzi, R. Čaplar, F. Jundt, P. Crochet, Y. Leifels, C. Pinkenburg, D. Moisa, Th. Blaich, S. C. Jeong, S. Hölbling, G. Guillaume, M. Dželalija, C. Cerruti, T. Wienold, Pascal Dupieux, B. Sikora, R. Dona, G. S. Wang, James Ritman, Mihai Petrovici, M. A. Vasiliev, J. Biegansky, G. Mgebrishvili, V. T. Smolyankin, P. Koncz, P. Pras, Y. Korchagin, Z. Seres, Z. G. Fan, Christian Claude Kuhn, Fouad Rami, K. M. Teh, V. Simion, J. P. Coffin, I. Belyaev, K. Siwek-Wilczyńska, C. Roy, J. Keczkemeti, M. Kirejczyk, Nicole Bastid, L. Tizniti, M. Krämer, D. Schüll, K. Wisniewski, A. Sadchikov, I. Legrand, B. Hong, P. Wagner, R. Kotte, D. Pelte, J. Mösner, W. Reisdorf, Vladislav Manko, A. Buta, R. P. Freifelder, A. Zhilin, V. Amouroux, K. D. Hildenbrand, E. Erö, A.L. Lebedev, J. P. Alard, Z. Fodor, and A. Gobbi

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Phase (waves), Charge (physics), Nuclear matter, Azimuth, Nuclear physics, Nuclear Reactions, Au-197 (Au-197, X), E=100-800 MeV/nucleon, Azimuthal anisotropy, Out-of-plane emission, Atomic physics, Nuclear Experiment, Anisotropy, Saturation (magnetic), Beam (structure)
Abstract

We present new experimental results concerning the azimuthal distributions of proton-likes, light and intermediate mass fragments at midrapidity for Au(100-800 AMeV)+Au collisions measured with the FOPI phase-I detector at GSI in Darmstadt. The azimuthal distributions are investigated as a function of the collision centrality, the incident energy, the fragment charge and transverse momentum. The azimuthal anisotropy is maximum for impact parameters around 7 fm. Intermediate mass fragments present a stronger out-of-plane emission signal than light fragments and a saturation is reached for Z greater than or equal to 4. The azimuthal anisotropy increases with the fragment transverse momentum and decreases as the incident energy increases. The azimuthal anisotropy of Z = 2 particles investigated as a function of the scaled fragment transverse momentum follows an universal curve for bombarding energies between 250-800 AMeV. A signature for a transition from in-plane to out-of-plane emission is evidenced at the lowest beam energies.

Published
1997
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3. Charged pion production in Au on Au collisions at 1 AGeV The FOPI Collaboration

Author

Y. Leifels, Christian Claude Kuhn, E. Häfele, D. Best, Mihai Petrovici, U. Sodan, G. Goebels, James Ritman, A. Gobbi, Peter Wagner, Z. Seres, R. Čaplar, J. Mösner, W. Reisdorf, Vladislav Manko, Y. Korchagin, V. T. Smolyankin, P. Pras, I. Belyaev, J. P. Coffin, A. Buta, D. Moisa, D. Wohlfarth, A. Genoux-Lubain, V. Ramillien, G. Guillaume, G.S. Wang, F. Jundt, P. Crochet, V. Simion, D. Lambrecht, A. Zhilin, C. Roy, M. Eskef, Z. Fodor, P. Koncz, V. Amouroux, R. Kotte, M. Kirejczyk, J. P. Alard, T. Wienold, D. Pelte, J. Biegansky, M. A. Vasiliev, Anton Andronic, D. Schüll, I. Legrand, J. Kecskemeti, Nicole Bastid, P. Fintz, Fouad Rami, N. Herrmann, C. Pinkenburg, M. Korolija, Byung-Sik Hong, Alexandre Lebedev, B. Sikora, W. Neubert, M. Trzaska, N. Cindro, Pascal Dupieux, H. Merlitz, S. Mohren, J. Erö, K. D. Hildenbrand, K. Siwek-Wilczyńska, Z. Basrak, and M. Dzelalija

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Equation of state, Nuclear Theory, Kinetic energy, Spectral line, Momentum, Nuclear physics, Pion, Nuclear fusion, Hermetic detector, High Energy Physics::Experiment, Rapidity, Nuclear Experiment
Abstract

Charged pions are measured with the 4π detector FOPI at GSI using the Au on Au reaction at 1.06 AGeV bombarding energy. The pion multiplicities ngp increase with the number of participants Apart. The average pion multiplicities per participant are #### and #### These values are only half as large as extrapolated from the low-mass systems studied by Harris et al. The ratio #### increases with Apart and decreases with the pion kinetic energies. The pion kinetic energy spectra have concave shapes, their parametrization in terms of thermal Boltzmann distributions yields a low (T l,π) and high (Th,π) temperature which change with the cm emission angle Θ of the pions. In the angular range 45dg is larger than , the high temperatures , are, within experimental uncertainties, the same. The inclusive polar angular distributions of pions are anisotropic, dσ/dΩ increases for forward and backward angles. The forward — backward enhancements are independent of the pion kinetic energies or the number of participants. In addition to the preferred forward — backward emission, also the enhanced emission into the transverse direction Θ = 90° is observed for pions with high energies or for pions from near-central collisions. These observations and the shape of the rapidity spectra suggest that pions, emitted from the central rapidity region, are partly rescattered by spectator matter. The strength of the rescattering process depends only weakly on the number of participants. The experimental data are compared to the results of IQMD/GEANT calculations using momentum dependent NN interactions and a hard equation of state. The calculated pion multiplicities are approximately 50% larger than experimentally determined; the existence of secondary pion sources is reproduced by the calculation, but their predicted strengths are larger than experimentally observed.

Published
1997
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4. Shape of collective flow in highly central Au(150 A MeV)+Au collisions

Author

J. Biegansky, Peter Wagner, F. Jundt, D. Schüll, I. Legrand, A. Sadchikov, M. A. Vasiliev, V. Simion, P. Fintz, D. Best, A. Zhilin, G.S. Wang, C. Roy, S. C. Jeong, Fouad Rami, P. Crochet, S. Hölbling, Z. Seres, K. D. Hildenbrand, Z. G. Fan, Byung-Sik Hong, R. Kotte, G. Mgebrishvili, V. T. Smolyankin, P. Pras, D. Pelte, Mihai Petrovici, U. Sodan, Christian Claude Kuhn, C. Maazouzi, N. Herrmann, W. Neubert, C. Pinkenburg, Y. Leifels, J. P. Coffin, B. Sikora, James Ritman, H. Stöcker, Z. Basrak, J. Kecskemeti, M. Dzelalija, P. Koncz, Y. Korchagin, D. Wohlfarth, T. Wienold, Pascal Dupieux, Z. Fodor, A. Lebedev, Nicole Bastid, L. Fraysse, M. Trzaska, N. Cindro, L. Tizniti, J. P. Wessels, R. Čaplar, R. Donà, Vladislav Manko, V. Amouroux, J. P. Alard, I. Belyaev, M. Kirejczyk, D. Moisa, J. Mösner, A. Buta, G. Guillaume, J. Konopka, A. Gobbi, W. Reisdorf, Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and FOPI

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Flow (psychology), Degrees of freedom (physics and chemistry), Nuclear Reactions. Heavy ion collisions. Nuclear matter flow. Clusters, pacs:25.70.-z, 01 natural sciences, Charged particle, Nuclear physics, Cross section (physics), Transverse plane, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear fusion, Selection method, Polar coordinate system, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Using the FOPI facility at GSI, charged particles (1 ≤Z≤6) produced in the Au(150 A MeV)+Au reaction have been measured at laboratory angles 1.20 < Θlab < 300. Highly central collisions have been selected with two criteria, both dealing with the longitudinal and transverse degrees of freedom of the reaction. The relevance of this selection method is supported by QMD calculations which indicate that such criteria are able to select mean impact parameters less than 2 fm. Bias effects introduced by the criteria have been evaluated. The centre-of-mass polar angle distributions of low energy clusters emitted in these central collisions, have been extracted: the intensity ratio deduced for a transverse to longitudinal emission is found to be R= 1.4 −0.4 +0.2 . Model comparisons using QMD are presented. The value of R appears to depend sensitively on the nucleon-nucleon cross section, σnn. Within this model, a value of σ=25+ - 5 mb is derived.

Published
1997
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5. Central collisions of Au on Au at 150, 250 and 400 A·MeV

Author

W. Reisdorf, D. Best, A. Gobbi, N. Herrmann, K.D. Hildenbrand, B. Hong, S.C. Jeong, Y. Leifels, C. Pinkenburg, J.L. Ritman, D. Schüll, U. Sodan, K. Teh, G.S. Wang, J.P. Wessels, T. Wienold, J.P. Alard, V. Amouroux, Z. Basrak, N. Bastid, I. Belyaev, L. Berger, J. Biegansky, M. Bini, S. Boussange, A. Buta, R. Čaplar, N. Cindro, J.P. Coffin, P. Crochet, R. Dona, P. Dupieux, M. Dželalija, J. Erö, M. Eskef, P. Fintz, Z. Fodor, L. Fraysse, A. Genoux-Lubain, G. Goebels, G. Guillaume, Y. Grigorian, E. Häfele, S. Hölbling, A. Houari, M. Ibnouzahir, M. Joriot, F. Jundt, J. Kecskemeti, M. Kirejczyk, P. Koncz, Y. Korchagin, M. Korolija, R. Kotte, C. Kuhn, D. Lambrecht, A. Lebedev, I. Legrand, C. Maazouzi, V. Manko, T. Matulewicz, P.R. Maurenzig, H. Merlitz, G. Mgebrishvili, J. Mösner, S. Mohren, D. Moisa, G. Montarou, I. Montbel, P. Morel, W. Neubert, A. Olmi, G. Pasquali, D. Pelte, M. Petrovici, G. Poggi, P. Pras, F. Rami, V. Ramillien, C. Roy, A. Sadchikov, Z. Seres, B. Sikora, V. Simion, K. Siwek-Wilczyńska, V. Smolyankin, N. Taccetti, R. Tezkratt, L. Tizniti, M. Trzaska, M.A. Vasiliev, P. Wagner, K. Wisniewski, D. Wohlfarth, and A. Zhilin

Subjects
Physics, selected central collisions, Nuclear and High Energy Physics, Angular range, E=150 and 250 and 400 MeV/nucleon, Isotope, charges and yields, comparison to statistical multifragmentation models, FOS: Physical sciences, deduced radial flow, measured fragment velocity vectors, Effective nuclear charge, Charged particle, Azimuth, Nuclear physics, Transverse plane, Cross section (physics), NUCLEAR REACTIONS Au(Au,X), chemical composition, Nuclear Experiment (nucl-ex), Nuclear Experiment, Quantum, quantum molecular dynamics model
Abstract

Collisions of Au on Au at incident energies of 150, 250 and 400 A MeV were studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (Z < 16) and velocity of the products were detected with full azimuthal acceptance at laboratory angles of 1-30 degrees. Isotope separated light charged particles were measured with movable multiple telescopes in an angular range of 6-90 degrees. Central collisions representing about 1 % of the reaction cross section were selected by requiring high total transverse energy, but vanishing sideflow. The velocity space distributions and yields of the emitted fragments are reported. The data are analysed in terms of a thermal model including radial flow. A comparison with predictions of the Quantum Molecular Model is presented., LateX text 62 pages, plus six Postscript files with a total of 34 figures, accepted by Nucl.Phys.A

Published
1997
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6. Evidence for collective expansion in light-particle emission following Au+Au collisions at 100, 150 and 250 A·MeV

Author

Z. Basrak, P. Morel, R. Tezkratt, A. Sadchikov, Nello Taccetti, K. D. Hildenbrand, J. P. Alard, R. Dona, Mihai Petrovici, R. Freifelder, Y. Korchagin, A. Houari, J. P. Wessels, G. Mgebrishvili, I. Legrand, V. Ramillien, Gabriele Pasquali, M. Krämer, Nicole Bastid, M. Dželalija, G. Guillaume, A. Buta, Pascal Dupieux, F. Jundt, P. Koncz, J. Erö, P. Wagner, Z. Seres, P. R. Maurenzig, D. Wohlfarth, J. Mösner, P. Fintz, J. P. Coffin, Y. Grigorian, Th. Blaich, Vladislav Manko, R. Kotte, D. Pelte, Christian Claude Kuhn, Gerard Montarou, T. Wienold, S. Hölbling, V. Simion, S. Frolov, D. Moisa, U. Sodan, Z.G. Fan, D. Schüll, M. A. Vasiliev, I. M. Belayev, A. Zhilin, F. Rami, V. Amouroux, J. Kecskemeti, S. Smolyankin, N. Herrmann, Alexandre Lebedev, B. Sikora, W. Neubert, W. Reisdorf, Alessandro Olmi, Z. Wilhelmi, R. Čaplar, A. Gobbi, M. Ibnouzahir, S. Boussange, C. Maguire, L. Berger, C. Cerruti, Zoltan Fodor, S. C. Jeong, Giacomo Poggi, Maurizio Bini, Pawel Danielewicz, I. Montbel, L. Fraysse, M. Trzaska, and N. Cindro

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Range (particle radiation), Isotope, Hydrogen, Phase (waves), chemistry.chemical_element, Kinetic energy, Spectral line, Coincidence, Nuclear physics, chemistry, Atomic physics, Nuclear Experiment
Abstract

Light-particle emission from Au+Au collisions has been studied in the bombarding-energy range 100–250 A ·MeV, using ΔE − E R telescopes in coincidence with the FOPI detector in its phase I configuration. Center-of-mass energy spectra have been measured for Z = 1,2 isotopes emitted in central collisions at CM polar angles between 60° and 90°. Evidence for a collective expansion is reported, on the basis of the mean kinetic energies of hydrogen isotopes. Comparison is presented with statistical calculations (WIX code). For CM kinetic energy spectra, fair agreement is found between data and a recently developed transport model.

Published
1995
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7. Central Au on Au collisions

Author

J. Erö, L. Berger, S. Mohren, J. Biegansky, D. Wohlfarth, Z. Basrak, James Ritman, D. Moisa, F. Jundt, W. Reisdorf, M. Dzelalija, Giacomo Poggi, Y. Korchagin, A. Zhilin, Fouad Rami, K.D. Hildenbrand, P. R. Maurenzig, I. Montbel, E. Häfele, Z. Fodor, V. Simion, R. Bock, D. Best, A. Gobbi, Gabriele Pasquali, Christian Claude Kuhn, M. Krämer, Adriano Gobbi, Mihai Petrovici, N. Herrmann, C. Cerruti, R. Kotte, U. Sodan, G. Goebels, S. Hölbling, W.Q. Shen, D. Pelte, M. A. Vasiliev, S. Boussange, V. Ramillien, C. Pinkenburg, J. P. Coffin, R. Dona, K. Siwek-Wilczyńska, J. Kecskemeti, P. Wagner, V. Amouroux, G. Mgebrishvili, Ch. Roy, B. Sikora, J. Mösner, A. Buta, M. Trzaska, D. Schüll, I. Legrand, Y. Leifels, G. Guillaume, Maurizio Bini, S. Smolyankin, I. M. Belayev, Nello Taccetti, G.S. Wang, P. Fintz, Alessandro Olmi, R. Čaplar, Y. Yatsounenko, A.L. Lebedev, Vladislav Manko, T. Wienold, J. P. Alard, Pascal Dupieux, L. Fraysse, M. Kowalczyk, N. Cindro, A. Houari, Nicole Bastid, W. Neubert, and M. Kirejczyk

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics
Published
1995
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8. Mass dependence of π0-production in heavy ion collisions at 1 A GeV

Author

V. Metag, S.C. Jeong, J. Ritman, H. W. Wilschut, D. Wohlfahrt, T. Wienold, R.S. Simon, M. Röbig-Landau, O. Schwalb, S. Hlavac, K. Teh, L.B. Venema, W. Kühn, Pascal Dupieux, R. W. Novotny, A. E. Raschke, U. Sodan, Nicole Bastid, Johannes Peter Wessels, J. P. Alard, Michal Sumbera, Gerard Montarou, W. Neubert, M. Franke, F. D. Berg, N. Herrmann, K. D. Hildenbrand, N. Brummund, Herbert Löhner, A. Gobbi, M. Pfeiffer, M. Notheisen, and Research unit Medical Physics

Subjects
Physics, DYNAMICS, Nuclear and High Energy Physics, High energy, Argon, COLLECTIVE FLOW, Krypton, Nuclear Theory, NUCLEUS-NUCLEUS COLLISIONS, Collision system, chemistry.chemical_element, PION-PRODUCTION, STATE, Nuclear physics, ENERGY, Pion, chemistry, Cascade, EQUATION, Heavy ion, PARTICLE-PRODUCTION, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, MATTER
Abstract

The production of neutral pions has been studied in the reactions 40 Ar + nat Ca , 86 Kr + nat Zr and 197 Au + 197 Au at 1 A GeV. For high energy pions emitted from the heavier systems a steeper than linear rise of the pion multiplicity with the centrality of the reaction is observed, indicating a pion production process other than binary nucleon-nucleon collisions. At low transverse momenta an enhancement of the π 0 -multiplicity increasing with the mass of the collision system is found. Systematic discrepancies between the experimental results and recent BUU, QMD and Cascade calculations are discussed.

Published
1994

9. Velocity correlations of intermediate mass fragments produced in central collisions of Au+Au atE=150AMeV

Author

O. Houari, Z. Wilhelmi, A.L. Lebedev, C. Maguire, I. M. Belayev, M. Krämer, P. Koncz, D. Moisa, J. Mösner, D. Wohlfarth, G. Montaru, A. Sadchikov, M. A. Vasiliev, V. Simion, Vladislav Manko, R. Freifelder, A. Buta, D. Schüll, J. P. Wessels, Z. Basrak, F. Jundt, I. Legrand, Fouad Rami, S. Frolov, G. Guillaume, W. Reisdorf, R. Kotte, J. P. Alard, K. Teh, D. Pelte, P. Wagner, B. Sikora, Mihai Petrovici, N. Herrmann, S. C. Jeong, Y. Korchagin, U. Sodan, A. L. Zhilin, Z. G. Fan, K. D. Hildenbrand, J. Kecskemeti, R. Čaplar, S. Smolyankin, I. Montbel, G. Mgebrishvili, R. Tezkratt, A. Gobbi, L. Fraysse, M. Trzaska, Nicole Bastid, M. Jorio, Z. Seres, Th. Blaich, S. Hölbling, N. Cindro, J. Erö, J. P. Coffin, T. Matulewicz, C. Cerruti, W. Neubert, Christian Claude Kuhn, Zoltan Fodor, P. Morel, Pascal Dupieux, Y. Grigorian, T. Wienold, P. Fintz, and B. Kämpfer

Subjects
Nuclear physics, Nuclear reaction, Physics, Azimuth, Nuclear and High Energy Physics, Fragmentation (mass spectrometry), Detector, Coulomb, Interaction model, Atomic physics, Nuclear Experiment, Beam energy
Abstract

Velocity correlations of intermediate mass fragments (IMFs), produced in central collisions of Au+Au at 150 MeV beam energy, are extracted from measurements with the FOPI (phase I) detector system at SIS in GSI Darmstadt. The IMF correlation function for semicentral events is found to be affected by the directed sideward flow. When rotating the events into a unique reaction plane an enhancement of correlations, resulting from event mixing effects, vanishes. Selecting violent collisions with a high degree of azimuthal symmetry the correlation function appears nearly independent of additional event or single particle gate conditions. The comparison of the data with a Coulomb dominated final-state interaction model points to an expanding and multifragmenting soure with radius [ital R][similar to]14 fm.

Published
1993
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10. Entropy production in the Au+Au reaction between 150Aand 800AMeV

Author

J. Mösner, A. Buta, R. Kotte, D. Pelte, G. Guillaume, L. Fraysse, Gerard Montarou, Y. Korchagin, I. Montbel, M. Jorio, B. Sikora, Z. Seres, F. Jundt, S. Boussange, C. Cerruti, D. Schüll, I. Legrand, R. Freifelder, J. Konopka, Z. Basrak, P. Koncz, T. Wienold, K. Teh, Fouad Rami, A. Gobbi, S. Frolov, D. Wohlfarth, S. Smolyankin, S. Ramillien, Z. Wilhelmi, J. P. Coffin, Christian Claude Kuhn, J. Kecskemeti, Mihai Petrovici, J. P. Wessels, C. Maguire, U. Sodan, Y. Grigorian, I. M. Belayev, M. Krämer, Pascal Dupieux, Peter Wagner, W. Reisdorf, A. Sadchikov, Z. Fodor, Z. G. Fan, P. Fintz, D. Moisa, M. Trzaska, V. Simion, N. Cindro, N. Herrmann, K. D. Hildenbrand, T. Matulewicz, Th. Blaich, S. Hölbling, J. Erö, L. Berger, A. Houari, Alexandre Lebedev, W. Neubert, Vladislav Manko, A. Zhilin, J. P. Alard, R. Čaplar, Nicole Bastid, R. Tezkratt, M. A. Vasiliev, S. C. Jeong, R. Dona, and G. Mgebrishvili

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Entropy (classical thermodynamics), Entropy production, Atomic physics
Published
1993
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11. A highly-segmented ΔE-time-of-flight wall as forward detector of the 4π-system for charged particles at the SIS/ESR accelerator

Author

M. A. Vasiliev, V. Simion, M. Crouau, G. Augustinski, J.P. Coffin, D. Vincent, F. Hornecker, S. Frolov, M. Marquardt, R. Freifelder, Z. Basrak, C. Cerruti, R. Kotte, N. Herrmann, L. Fraysse, B. Sikora, S. C. Jeong, Gerard Montarou, Z. G. Fan, Y. Grigorian, P. Koncz, S. Smolyankin, P. Morel, W. Reisdorf, R. Bock, D. Wohlfarth, R. Čaplar, N. Cindro, G. Mgebrishvili, J. Erö, A. Gobbi, R. Neunlist, G. Ortlepp, J.P. Wessels, P. Boccaccio, E. Sahuc, J.P. Alard, C. Kuhn, M. Jorio, J. Mösner, E. Gimenez, Vladislav Manko, C. Maguire, T. Matulewicz, S. Boussange, A. Buta, Y. Korchagin, I. Montbel, N. Bastid, D. Schüll, I. Legrand, Th. Blaich, Z. Fodor, I. M. Belayev, M. Krämer, G. Guillaume, S. Hölbling, R. J. Charity, Z. Seres, M.A. Saettel, D. Moisa, P. Fintz, F. Rami, P. Dupieux, B. Tischler, T. Wienold, J. Kecskemeti, J. Weinert, A. Houari, R. Tezkratt, M. Trzaska, W. Neubert, D. Pelte, A.L. Lebedev, P. Wagner, Mihai Petrovici, U. Sodan, J.F. Devin, K.D. Hildenbrand, M.H. Tanaka, F. Jundt, A. Zhilin, K. Teh, F. Daudon, C. Fayard, S. Mayade, Z. Wilhelmi, and G. Savinel

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Wire chamber, Physics::Instrumentation and Detectors, Nuclear Theory, Detector, Scintillator, Particle detector, Charged particle, Nuclear physics, Time of flight, Ionization chamber, Atomic physics, Nuclear Experiment, Instrumentation
Abstract

At the SIS/ESR accelerator facility at GSI in Darmstadt the 4π-detector system FOPI is under construction at present. It is designed for the investigation of central collisions of heavy ions in the energy range up to 2 A GeV. As phase I of this detector a forward wall has been built and used in various experiments. It comprizes a total number of 764 scintillators with an additional shell of 188 thin ΔE -detectors in front of it and covers the full azimuth of the polar angles from 1° to 30°. The velocity and the nuclear charge of the fragments are determined by a combined time-of-flight and ΔE measurement.

Published
1993
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12. Midrapidity source of intermediate-mass fragments in highly central collisions of Au + Au at 150AMeV

Author

Alessandro Olmi, Y. Grigorian, Th. Blaich, P. Koncz, Z. Seres, T. Matulewicz, S. Hölbling, J. Kecskemeti, R. Tezkratt, D. Schüll, I. Legrand, M. Crouau, P. Fintz, R. Freifelder, J. P. Alard, M. A. Vasiliev, V. Simion, P. Morel, Z. Basrak, Fouad Rami, A. Sadchikov, F. Jundt, R. Kotte, Zoltan Fodor, Nello Taccetti, D. Pelte, C. Cerruti, R. Čaplar, Gerard Montarou, J. Erö, D. Moisa, A. Zhilin, Z. Wilhelmi, J. Mösner, K.D. Hildenbrand, K. Teh, T. Wienold, S. Smolyankin, A. Buta, Mihai Petrovici, U. Sodan, P. Wagner, G. Guillaume, S. C. Jeong, Gabriele Pasquali, W. Neubert, M. Jorio, Pascal Dupieux, G. Mgebrishvili, Y. Korchagin, Giacomo Poggi, J.P. Wessels, J. P. Coffin, W. Reisdorf, L. Fraysse, A. Gobbi, M. Trzaska, N. Cindro, Christian Claude Kuhn, C. Maguire, I. M. Belayev, M. Krämer, D. Wohlfarth, Z. G. Fan, Maurizio Bini, N. Herrmann, Vladislav Manko, B. Sikora, O. Houari, Nicole Bastid, A.L. Lebedev, S. Frolov, and R. Bock

Subjects
Physics, Nuclear physics, Nuclear reaction, Transverse plane, Isotope, General Physics and Astronomy, Incident energy, Isotopes of gold, Atomic physics, Nuclear Experiment, Selection criterion, Effective nuclear charge, Charged particle
Abstract

Charged particles have been observed in collisions of Au on Au at an incident energy of 150{ital A} MeV using a high-granularity detector system covering approximately the forward hemisphere in the center-of-mass system. Highly central collisions have been studied using a double selection criterion which combines large charged-particle multiplicities with small transverse-momentum directivities. In this class of events about one quarter of the total nuclear charge emerges as intermediate-mass fragments with nuclear charges {ital Z}{gt}2. These fragments are centered at midrapidity and are produced with large transverse velocities.

Published
1992
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13. Charged pions from Ni on Ni collisions between 1 and 2 AGeV

Author

J. P. Alard, M. Korolija, Pascal Dupieux, H. Merlitz, V. Ramillien, M. Trzaska, N. Cindro, T. Wienold, James Ritman, V. Amouroux, F. Jundt, C. Pinkenburg, Y. Korchagin, Byung-Sik Hong, D. Moisa, J. Erö, B. Sikora, I. Belyaev, E. Häfele, P. Crochet, Alexandre Lebedev, A. Zhilin, D. Best, Z. Seres, W. Neubert, G. Goebels, Anton Andronic, M. Kirejczyk, Z. Basrak, M. Dželalija, D. Schüll, I. Legrand, S. Mohren, J. Biegansky, P. Koncz, Y. Leifels, V. T. Smolyankin, P. Pras, J. P. Coffin, K. Siwek-Wilczyńska, N. Herrmann, K. D. Hildenbrand, Fouad Rami, R. Kotte, D. Pelte, Christian Claude Kuhn, M. A. Vasiliev, V. Simion, Nicole Bastid, J. Kecskemeti, W. Reisdorf, A. Gobbi, D. Lambrecht, J. Mösner, A. Buta, G. Guillaume, A. Genoux-Lubain, Vladislav Manko, R. Čaplar, M. Eskef, Z. Fodor, Peter Wagner, Mihai Petrovici, U. Sodan, G.S. Wang, P. Fintz, C. Roy, D. Wohlfarth, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and FOPI

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, Nuclear physics, Pion, Heavy ion Physics, Central Collisions, Charged Pions Production, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment
Abstract

Charged pions from Ni + Ni reactions at 1.05, 1.45 and 1.93 AGeV are measured with the FOPI detector. The mean $\pi^{\pm}$ multiplicities per mean number of participants increase with beam energy, in accordance with earlier studies of the Ar + KCl and La + La systems. The pion kinetic energy spectra have concave shape and are fitted by the superposition of two Boltzmann distributions with different temperatures. These apparent temperatures depend only weakly on bombarding energy. The pion angular distributions show a forward/backward enhancement at all energies, but not the $\Theta = 90^0$ enhancement which was observed in case of the Au + Au system. These features also determine the rapidity distributions which are therefore in disagreement with the hypothesis of one thermal source. The importance of the Coulomb interaction and of the pion rescattering by spectator matter in producing these phenomena is discussed., Comment: 22 pages, Latex using documentstyle[12pt,a4,epsfig], to appear in Z. Phys.A

Published
1997

14. Onset of Nuclear Matter Expansion in Au+Au Collisions

Author

P. Crochet, F. Rami, A. Gobbi, R. Dona, J.P. Coffin, P. Fintz, G. Guillaume, F. Jundt, C. Kuhn, C. Roy, B. de Schauenburg, L. Tizniti, P. Wagner, J.P. Alard, V. Amouroux, A. Andronic, Z. Basrak, N. Bastid, I. Belyaev, D. Best, J. Biegansky, A. Buta, R. Čaplar, N. Cindro, P. Dupieux, M. Dželalija, Z.G. Fan, Z. Fodor, L. Fraysse, R.P. Freifelder, N. Berrmann, K.D. Hildenbrand, B. Hong, S.C. Jeong, J. Kecskemeti, M. Kirejczyk, P. Koncz, M. Korolija, R. Kotte, A. Lebedev, Y. Leifels, V. Manko, D. Moisa, J. Mösner, W. Neubert, D. Pelte, M. Petrovici, C. Pinkenburg, P. Pras, V. Ramillien, W. Reisdorf, J.L. Ritman, A.G. Sadchikov, D. Schüll, Z. Seres, B. Sikora, V. Simion, K. Siwek-Wilczyńska, U. Sodan, K.M. Teh, M. Trzaska, M. Vasiliev, G.S. Wang, J.P. Wessels, T. Wienold, K. Wisniewski, D. Wohlfarth, and A. Zhilin

Subjects
Physics, Nuclear and High Energy Physics, Sideward-flow, Plane (geometry), FOS: Physical sciences, Threshold energy, Nuclear matter, Balance energy, Nuclear matter expansion, Squeeze-out, Nuclear force, Heavy ion collisions, Radial flow, Atomic physics, Impact parameter, Nuclear Experiment (nucl-ex), Transition energy, Nuclear Experiment, Beam (structure), Energy (signal processing), Excitation
Abstract

Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z>2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces., 26 pages Revtex, 6 ps-figures, to appear in Nucl.Phys.A

Published
1997
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15. Azimuthal anisotropies as stringent test for nuclear transport models

Author

P. Crochet, F. Rami, R. Donà, J.P. Coffin, P. Fintz, G. Guillaume, F. Jundt, C. Kuhn, C. Roy, B. de Schauenburg, L. Tizniti, P. Wagner, J.P. Alard, A. Andronic, Z. Basrak, N. Bastid, I. Belyaev, A. Bendarag, G. Berek, D. Best, J. Biegansky, A. Buta, R. Čaplar, N. Cindro, P. Dupieux, M. Dželalija, Z.G. Fan, Z. Fodor, L. Fraysse, R.P. Freifelder, A. Gobbi, N. Herrmann, K.D. Hildenbrand, B. Hong, S.C. Jeong, J. Kecskemeti, M. Kirejczyk, P. Koncz, M. Korolija, R. Kotte, A. Lebedev, Y. Leifels, V. Manko, D. Moisa, J. Mösner, W. Neubert, D. Pelte, M. Petrovici, C. Pinkenburg, W. Reisdorf, J.L. Ritman, A.G. Sadchikov, D. Schüll, Z. Seres, B. Sikora, V. Simion, K. Siwek-Wilczyńska, U. Sodan, K.M. Teh, M. Trzaska, G.S. Wang, J.P. Wessels, T. Wienold, K. Wisniewski, D. Wohlfarth, A. Zhilin, C. Hartnack, Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), FOPI, and Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Equation of state, 010308 nuclear & particles physics, Plane (geometry), FOS: Physical sciences, 01 natural sciences, 7. Clean energy, Charged particle, Momentum, Nuclear physics, Isospin, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Polar, Nuclear Experiment (nucl-ex), 010306 general physics, Anisotropy, Nuclear Experiment
Abstract

Azimuthal distributions of charged particles and intermediate mass fragments emitted in Au+Au collisions at 600AMeV have been measured using the FOPI facility at GSI-Darmstadt. Data show a strong increase of the in-plane azimuthal anisotropy ratio with the charge of the detected fragment. Intermediate mass fragments are found to exhibit a strong momentum-space alignment with respect of the reaction plane. The experimental results are presented as a function of the polar center-of-mass angle and over a broad range of impact parameters. They are compared to the predictions of the Isospin Quantum Molecular Dynamics model using three different parametrisations of the equation of state. We show that such highly accurate data provide stringent test for microscopic transport models and can potentially constrain separately the stiffness of the nuclear equation of state and the momentum dependence of the nuclear interaction., 26 pages Revtex, 7 ps-figures, to appear in Nucl.Phys.A

Published
1997

16. K^+ production in the reaction $^{58}Ni+^{58}Ni$ at incident energies from 1 to 2 AGeV

Author

J. Biegansky, I. Legrand, Christian Claude Kuhn, U. Sodan, G. Goebels, F. Jundt, J. Mösner, Mihai Petrovici, Vladislav Manko, A. Zhilin, D. Schüll, Pascal Dupieux, K. Wisniewski, P. Crochet, E. Häfele, Peter Wagner, N. Herrmann, K. D. Hildenbrand, S. Mohren, J. P. Coffin, D. Best, B. Sikora, James Ritman, M. Trzaska, R. Kotte, Nicole Bastid, D. Moisa, G. Berek, G. S. Wang, C. Pinkenburg, L. Tizniti, Z. Seres, Y. Korchagin, Fouad Rami, R. Cherbatchev, K. Siwek-Wilczyńska, W. Reisdorf, C. Maazouzi, A. Somov, T. Wienold, I. Belyaev, M. A. Vasiliev, D. Wohlfarth, J. Kecskemeti, M. Kirejczyk, V. T. Smolyankin, P. Pras, V. Amouroux, Z. Fodor, A. Gobbi, V. Simion, J. P. Alard, G. Guillaume, B. Hong, Y. Leifels, C. Roy, I. E. Yushmanov, A. Genoux-Lubain, Alexandre Lebedev, W. Neubert, and D Pelte

Subjects
Physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, FOS: Physical sciences, Nuclear matter, Spectral line, Nuclear physics, Dispersion relation, Phase space, Transverse mass, Rapidity, Atomic physics, Multiplicity (chemistry), Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Semi-inclusive triple differential multiplicity distributions of positively charged kaons have been measured over a wide range in rapidity and transverse mass for central collisions of $^{58}$Ni with $^{58}$Ni nuclei. The transverse mass ($m_t$) spectra have been studied as a function of rapidity at a beam energy 1.93 AGeV. The $m_t$ distributions of K^+ mesons are well described by a single Boltzmann-type function. The spectral slopes are similar to that of the protons indicating that rescattering plays a significant role in the propagation of the kaon. Multiplicity densities have been obtained as a function of rapidity by extrapolating the Boltzmann-type fits to the measured distributions over the remaining phase space. The total K^+ meson yield has been determined at beam energies of 1.06, 1.45, and 1.93 AGeV, and is presented in comparison to existing data. The low total yield indicates that the K^+ meson can not be explained within a hadro-chemical equilibrium scenario, therefore indicating that the yield does remain sensitive to effects related to its production processes such as the equation of state of nuclear matter and/or modifications to the K^+ dispersion relation., Comment: 24 pages Latex (elsart) 7 PS figures to be submitted to Nucl. Phys A

Published
1997
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17. Proton-proton correlations in central collisions of Ni+Ni at 1.93 AGeV and the space-time extent of the emission source

Author

A. Lebedev, M. Korolija, Y. Leifels, E. Haefele, I. Belyaev, V. Amouroux, Mihai Petrovici, V. Simion, U. Sodan, D. Wohlfarth, I. Legrand, S. Hoelbling, James Ritman, C. Plettner, Z. Fodor, J. Kecskemeti, M. Kirejczyk, J. P. Coffin, Y. Yatsunenko, S. Mohren, A. Gobbi, Christian Claude Kuhn, F. Jundt, G. Berek, Z. Basrak, C. Roy, G. Goebels, J. Biegansky, Byung-Sik Hong, D. Best, K. Siwek-Wilczyńska, W. Neubert, R. Dona, A. Genoux-Lubain, Peter Wagner, Vladislav Manko, A. Somov, P. Pras, N. Herrmann, T. Wienold, M. Eskef, K. D. Hildenbrand, G.S. Wang, C. Maazouzi, A. Zhilin, M. Dzelalija, P. Crochet, Fouad Rami, J. P. Alard, R. Čaplar, P. Fintz, J. Moesner, R. Kotte, D. Pelte, L. Fraysse, A. Buta, Nicole Bastid, G. Guillaume, D. Schuell, Z. Seres, W. Reisdorf, Pascal Dupieux, H. Merlitz, M. Trzaska, N. Cindro, L. Tizniti, C. Pinkenburg, M.A. Vasilev, and B. Sikora

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Proton, Hadron, Radius, Rest frame, Heavy ion Physics, Central Collisions, Proton-proton correlations, Nuclear physics, Baryon, Correlation function (statistical mechanics), Atomic physics, Nucleon, Nuclear Experiment
Abstract

Small-angle correlations of proton pairs produced in central Ni+Ni collisions at a beam energy of 1.93 A.GeV are investigated with the FOPI detector system at GSI Darmstadt. Simultaneous comparison of longitudinal and transverse correlation functions with the predictions of the Koonin model allows to unravel the space-time ambiguity of the source extension. The determination of the source rest frame is found essential for the identification of this effect. For the present system, the selection of central events comprising about 8 % of the total cross section allows for the isolation of a compact source in momentum space which is centered around the c.m. velocity of the colliding nuclei. Taking into account the strong collective expansion of the participant zone, which introduces a reduction of the extracted source radius of more than 30 %, r.m.s. radius and emission time parameters of R-rms = (4.2 +/- 1.2) fm and t(rms) = (11(-5)(+7)) fm/c are extracted, respectively. In contrast, the analysis of the angle-integrated correlation function mixes the spatial and temporal size of the source and gives an upper limit R-rms = (7.0 +/- 0.8) fm of the source radius.

Published
1997
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18. Entropy in central Au+Au reactions between 100 and 400A MeV

Author

Z. Wilhelmi, L. Fraysse, M. Trzaska, F. Jundt, Alessandro Olmi, N. Cindro, D. Schüll, I. Legrand, W. Reisdorf, R. Dona, Zoltan Fodor, J. P. Alard, V. Amouroux, M. Ibnouzahir, P. Koncz, G. Mgebrishvili, N. Herrmann, K. D. Hildenbrand, A. Zhilin, R. Kotte, D. Moisa, D. Pelte, Gerard Montarou, P. Pras, J. Erö, I. M. Belayev, Giacomo Poggi, M. Krämer, S. Smolyankin, L. Berger, Z. Seres, Nello Taccetti, Nicole Bastid, R. Tezkratt, J. Biegansky, Gabriele Pasquali, Pascal Dupieux, V. Ramillien, P. Fintz, C. Cerruti, Mihai Petrovici, J. Mösner, U. Sodan, A. Houari, J. P. Wessels, J. P. Coffin, B. Sikora, S. Boussange, Fouad Rami, R. Čaplar, A. Buta, Z. Basrak, D. Wohlfarth, Alexandre Lebedev, Vladislav Manko, W. Neubert, G. Guillaume, J. Kecskemeti, T. Wienold, P. R. Maurenzig, S. Hölbling, M. A. Vasiliev, V. Simion, M. Dzelalija, P. Wagner, Maurizio Bini, A. Gobbi, Y. Korchagin, I. Montbel, and Christian Claude Kuhn

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Entropy (classical thermodynamics)
Published
1995

19. Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au+Au at E=(100-400)A MeV

Author

D. Schüll, I. Legrand, Pascal Dupieux, M. Trzaska, N. Cindro, Zoltan Fodor, Z. Wilhelmi, J. P. Alard, D. Wohlfarth, Th. Blaich, P. Fintz, S. Boussange, B. Kämpfer, W. Reisdorf, Y. Grigorian, P. Koncz, S. Hölbling, R. Kotte, R. Čaplar, D. Pelte, L. Fraysse, Gerard Montarou, J. Kecskemeti, S. Frolov, R. Freifelder, Z. Basrak, Z. G. Fan, Fouad Rami, N. Herrmann, K. D. Hildenbrand, V. Ramillien, Y. Korchagin, T. Matulewicz, B. Sikora, I. Montbel, Peter Wagner, Alexandre Lebedev, J. Erö, W. Neubert, V. Amouroux, A. Sadchikov, Vladislav Manko, J. P. Wessels, Christian Claude Kuhn, L. Berger, O. Houari, R. Tezkratt, J. P. Coffin, Mihai Petrovici, S. Smolyankin, U. Sodan, C. Cerruti, J. Mösner, M. Ibnouzahir, T. Wienold, F. Jundt, A. Buta, A. Zhilin, K. Teh, Z. Seres, G. Guillaume, D. Moisa, S. C. Jeong, R. Dona, G. Mgebrishvili, P. Pras, M. A. Vasiliev, V. Simion, I. M. Belayev, M. Krämer, A. Gobbi, and Nicole Bastid

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Range (particle radiation), Coulomb, Charge (physics), Radius, Atomic physics, Nuclear Experiment, Nucleon, Nuclear matter, Energy (signal processing), Spectral line
Abstract

Velocity correlations of intermediate mass fragments (IMF), produced in collisions of Au+Au at 100, 150, 250, and 400{ital A} MeV beam energy, are extracted from measurements with the 4{pi} detector system (FOPI) in construction stage I at Schwerionen-Synchrotron (SIS) at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt. The IMF correlation functions of peripheral and semicentral events are found to be strongly affected by the collective sideward motion of nuclear matter. The sideflow causes an enhancement of correlations at small relative velocities. This enhancement results from the mixing of differently azimuthally oriented events; it vanishes if the events are rotated into a unique reaction plane. Selecting violent central collisions, the comparison of the data with a Coulomb dominated final-state interaction model points to a radius of the expanding and multifragmenting source of {ital R}{sub {ital s}}{congruent}13 fm for 100{ital A} MeV which appears shrinking by 20% when increasing the projectile energy to 400 MeV per nucleon. The deduced source radii are found to depend on the radial explosion energy used in the model. The inclusion of such a collective expansion is necessary for a reasonable description of the experimental single-particle spectra of the IMF. The unique Coulomb suppression of small relativemore » IMF velocities, found for the given beam energy range, is attributed to rather constant averaged next-neighbor distances {l_angle}{ital d}{sub IMF}{r_angle}=8.6{plus_minus}0.2 fm of the IMF charge centers within the source at breakup time.« less

Published
1995

20. Sideward flow in Au + Au collisions at 400 A.MeV

Author

C. Khun, Giacomo Poggi, C. Hartnack, D. Schüll, J. Mösner, A. Buta, R. P. Freifelder, Pascal Dupieux, Gabriele Pasquali, G. Guillaume, Z. Wilhelmi, P. Wagner, Vladislav Manko, Mihai Petrovici, P. Koncz, Y. Gregorian, Z. Seres, L. Berger, S. C. Jeong, A. Sadchikov, A. Gobbi, S. Boussange, R. Kotte, D. Pelte, Gerard Montarou, I. Montbel, L. Fraysse, Alessandro Olmi, F. Rami, Maurizio Bini, Nicole Bastid, S. Frolov, R. Dona, M. Trzaska, I. M. Belayev, D. Moisa, U. Sodan, M. Krämer, N. Herrmann, N. Cindro, V. Amouroux, G. Mgebrishvili, P. Pras, F. Jundt, B. Sikora, J. P. Alard, A. Zhilin, P. Fintz, D. Wohlfarth, V. Simion, Z. Basrak, J. P. Wessels, Th. Blaich, V. Ramillien, R. Čaplar, R. Tezkratt, S. Hölbling, I. Legrand, K. M. Teh, Y. Korchagin, C. Cerruti, J. Erö, P. R. Maurenzig, T. Wienold, K. D. Hildenbrand, J. P. Coffin, Alexandre Lebedev, A. Houari, W. Neubert, S. Smolyankin, W. Reisdorf, C. Maguire, Zoltan Fodor, Z. G. Fan, M. Ibnouzahir, M. A. Vasiliev, J. Kecskemeti, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and FOPI

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Nuclear Theory, Detector, Observable, 01 natural sciences, 7. Clean energy, Nuclear physics, Formalism (philosophy of mathematics), 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Incident energy, Nuclear Experiment, 010306 general physics
Abstract

We present new experimental data obtained with the FOPI detector at SIS, for the Au + Au heavy-ion collisions at 400 A MeV incident energy. The sideward flow, determined from a method without reaction-plane reconstruction, and the nuclear stopping are studied as a function of the centrality of the collisions. In order to study the nuclear in-medium effects, which act on the NN cross sections and potential and hence on experimental observables like the nuclear-matter flow and stopping, these results are compared with the predictions of two different QMD versions. The first one offers a fully microscopic calculation of the cross sections and potential in the G-matrix formalism and naturally includes the in-medium effects (this version is for the first time confronted with experiment). The second one uses a standard Skyrme potential plus a momentum-dependent term in order to mimic the in-medium effects.

Published
1995

21. Collective motion in selected central collisions of Au on Au at 150A MeV

Author

J. P. Wessels, Vladislav Manko, Alessandro Olmi, Pascal Dupieux, S. Boussange, P. Wagner, Gabriele Pasquali, P. R. Maurenzig, R. Freifelder, P. Koncz, D. Wohlfarth, J. Erö, Z. Basrak, S. C. Jeong, J. P. Coffin, L. Berger, Maurizio Bini, R. Dona, Z. Wilhelmi, A.L. Lebedev, Y. Korchagin, A. Gobbi, G. Mgebrishvili, I. Montbel, F. Jundt, J. P. Alard, P. Morel, J. Kecskemeti, N. Herrmann, V. Ramillien, R. Čaplar, C. Maguire, Fouad Rami, J. Mösner, M. A. Vasiliev, V. Simion, I. M. Belayev, A. Zhilin, C. Cerruti, J. Randrup, K. Teh, A. Buta, M. Krämer, B. Sikora, Th. Blaich, G. Guillaume, S. Hölbling, Z. Seres, W. Reisdorf, K. D. Hildenbrand, D. Schüll, I. Legrand, Christian Claude Kuhn, D. Moisa, S. Frolov, Nicole Bastid, T. Wienold, R. Kotte, D. Pelte, Gerard Montarou, S. Smolyankin, Mihai Petrovici, U. Sodan, Zoltan Fodor, V. Amouroux, M. Ibnouzahir, A. Sadchikov, L. Fraysse, M. Trzaska, N. Cindro, Z. G. Fan, Giacomo Poggi, P. Fintz, Y. Grigorian, R. Tezkratt, A. Houari, and W. Neubert

Subjects
Physics, Nuclear reaction, Nuclear physics, Complete data, Collective model, General Physics and Astronomy, Collective motion, Atomic physics, Kinetic energy, Spectral line, Calculation methods
Abstract

Using the FOPI facility at GSI Darmstadt complete data of Au on Au collisions at 150[ital A] MeV were collected for charged products ([ital Z]=1--15) at laboratory angles 1[degree][le][Theta][sub lab][le]30[degree]. Central collisions were selected by applying various criteria. The kinetic energy spectra of fragments from an isolated midrapidity source are investigated in detail for center-of-mass angles 25[degree][le][Theta][sub c.m.][le]45[degree]. The heavy products ([ital Z][ge]3) are used to determine the collective energy which is found to be at least 10[ital A] MeV.

Published
1994

22. Azimuthal asymmetry of neutral pion emission in Au+Au reactions at 1 GeV/nucleon

Author

James Ritman, Y. Schutz, A. E. Raschke, H. P. Braak, R. Santo, J. Mösner, W. Kühn, A. Gobbi, Metag, U. Sodan, O. Schwalb, M. Pfeiffer, R. Kotte, S. Hlavac, M. Notheisen, R.S. Simon, K. Teh, D. Wohlfarth, W. Neubert, R.W. Ostendorf, T. Wienold, L.B. Venema, Herbert Löhner, Michal Sumbera, N. Brummund, R. Holzmann, F. D. Berg, N. Herrmann, K. D. Hildenbrand, Rudolf Siemssen, R. W. Novotny, H. W. Wilschut, J. P. Wessels, Research unit Medical Physics, Grand Accélérateur National d'Ions Lourds (GANIL), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, 25.75.+r, Meson, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, COLLECTIVE FLOW, Hadron, Nuclear Theory, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], HEAVY-ION COLLISIONS, MASS, Asymmetry, Charged particle, Nuclear physics, Baryon, Pion, PROJECTILE ENERGY, High Energy Physics::Experiment, Atomic physics, Nucleon, Nuclear Experiment, MATTER, media_common
Abstract

The azimuthal angle distributions of neutral pions at midrapidity from Au+Au reactions at 1 GeV/nucleon incident energy have been measured. An enhanced emission of [pi][sup 0]'s perpendicular to the reaction plane is observed. The azimuthal asymmetry is dependent on the [pi][sup 0] momentum: the [pi][sup 0] spectrum perpendicular to the reaction plane is harder than in the reaction plane. The strength of the observed asymmetry appears to be more pronounced for [pi][sup 0] than for charged particles and neutrons.

Published
1993
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23. Erratum to 'Azimuthal anisotropies as stringent test for nuclear transport models' [Nucl. Phys. A 627 (1997) 522–542]

Author

R. Freifelder, Z. G. Fan, D. Best, G. Berek, Byung-Sik Hong, M. Trzaska, P. Fintz, A. Bendarag, K. Siwek-Wilczyńska, W. Neubert, J. Biegansky, N. Cindro, L. Tizniti, V. Simion, K. Wisniewski, Anton Andronic, Z. Basrak, Peter Wagner, Z. Seres, Y. Leifels, A. Sadchikov, N. Herrmann, K. D. Hildenbrand, Mihai Petrovici, D. Moisa, U. Sodan, R. Čaplar, J. P. Alard, Fouad Rami, F. Jundt, Christian Claude Kuhn, C. Roy, G.S. Wang, S. C. Jeong, C. Pinkenburg, K. Teh, J. Kecskemeti, D. Wohlfarth, B. Sikora, Pascal Dupieux, A. Lebedev, R. Dona, J. P. Coffin, T. Wienold, Vladislav Manko, M. Delalija, D. Schüll, P. Koncz, A. Zhilin, B. de Schauenburg, P. Crochet, A. Gobbi, C. Hartnack, J. Mösner, I. Belyaev, R. Kotte, D. Pelte, L. Fraysse, A. Buta, W. Reisdorf, M. Kirejczyk, G. Guillaume, Nicole Bastid, James Ritman, Z. Fodor, J. P. Wessels, and M. Korolija

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Theoretical physics, Anisotropy
Abstract

R Crochet a, F. Rami a, R. Don~. a'b, J.R Coffin a, R Fintz a, G. Guillaume ~, F. Jundt a, C. Kuhn a, C. Roy a, B. de Schauenburg a, L. Tizniti ~, E Wagner a, J.E Alard c, A. Andronic d, Z. Basrak e, N. Bastid c, I. Belyaev f, A. Bendarag c, G. Berek i, D. BestL J. Biegansky h, A. Buta J, R. (~aplar e, N. Cindro e, E Dupieux c, M. D2elalija e, Z.G. Fan ~, Z. Fodor i, L. Fraysse ~, R.P. Freifelder g, A. Gobbi g, N. Hermlann g, K.D. Hildenbrand g, B. Hong g, S.C. Jeongg, J. Kecskemeti i, M. Kirejczyk j, P. Koncz i, M. Korolija e, R. Kotte h, A. Lebedev f'k, Y. Leifels g, V. Manko k, D. Moisa ~, J. M6sner n, W. Neubert h, D. Pelte e, M. Petrovici d, C. Pinkenburgg, W. Reisdorfg, J.L. Ritman g, A.G. Sadchikov k, D. Schtill g, Z. Seres i, B. SikoraJ, V. Simion a, K. Siwek-Wilczyfiska j, U. Sodan g, K.M. Teh g, M. Trzaska ~', G.S. Wang g, J.P. Wessels g, T. Wienold g, K. Wisniewski g, D. Wohlfarthh A. Zhilin f FOPI Collaboration, C. Hartnack m

Published
1998
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24. Erratum: Stopping and radial flow in central58Ni+58Nicollisions between1Aand2AGeV [Phys. Rev. C 57, 244 (1998)]

Author

E. Häfele, D. Best, A. Lebedev, Y. Leifels, N. Herrmann, J. Biegansky, K. D. Hildenbrand, W. Reisdorf, M. Eskef, P. Crochet, J. Kecskemeti, A. Genoux-Lubain, J. Mösner, Vladislav Manko, James Ritman, Nicole Bastid, Mihai Petrovici, C. Roy, U. Sodan, Z. Seres, Fouad Rami, T. Wienold, D. Wohlfarth, D. Schüll, M. A. Vasiliev, I. Legrand, A. Buta, A. Zhilin, I. Belyaev, B. de Schauenburg, G. Guillaume, J. P. Alard, C. Pinkenburg, G. Goebels, J. P. Coffin, M. Kirejczyk, Byung-Sik Hong, Christian Claude Kuhn, B. Sikora, A. Somov, R. Dona, A. Gobbi, Peter Wagner, P. Pras, F. Jundt, R. Kotte, D. Pelte, L. Fraysse, W. Neubert, V. Simion, G.S. Wang, G. Berek, K. Siwek-Wilczyńska, V. Amouroux, M. Trzaska, L. Tizniti, Z. Fodor, Pascal Dupieux, M. Korolija, C. Maazouzi, P. Fintz, and S. Mohren

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, Radial flow, 010306 general physics, 01 natural sciences
Published
1998
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27. Entropy in central Au+Au reactions between 100 and 400A MeV.

Author

Dzelalija M, Cindro N, Basrak Z, Caplar R, Hölbling S, Bini M, Maurenzig PR, Olmi A, Pasquali G, Poggi G, Taccetti N, Cerruti C, Coffin JP, Don R, Fintz P, Guillaume G, Houari A, Jundt F, Kuhn C, Rami F, Tezkratt R, Wagner P, Biegansky J, Kotte R, Mösner J, Neubert W, Wohlfarth D, Alard JP, Amouroux V V, Bastid N, Berger L, Belayev IM, Boussange S, Buta A, Dupieux P, Erö J, Fodor Z, Fraysse L, Gobbi A, Herrmann N, Hildenbrand KD, Ibnouzahir M, Kecskemeti J, Koncz P, Korchagin Y, Krämer M, Lebedev A, Legrand I I, Manko V V, Mgebrishvili G, Moisa D, Montarou G, Montbel I I, Pelte D, Petrovici M, Pras P, Ramillien V V, Reisdorf W, Schüll D, Seres Z, Sikora B, Simion V V, Smolyankin S, and Sodan U

Published
1995
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28. Cluster formation during expansion of hot and compressed nuclear matter produced in central collisions of Au on Au at 250A MeV.

Author

Petrovici M, Herrmann N, Legrand I I, Gobbi A, Hildenbrand KD, Reisdorf W, Buta A, Freifelder R, Jeong SC, Krämer M, Moisa D, Schüll D, Simion V V, Sodan U, Teh K, Wessels JP, Wienold T, Alard JP, Amouroux V V, Basrak Z, Bastid N, Belyaev IM, Berger L, Blaich T, Boussange S, Caplar R, Cerruti C, Cindro N, Coffin JP, Donà R, Dupieux P, Erö J, Fintz P, Fodor Z, Fraysse L, Guillaume G, Hölbling S, Houari A, Jundt F, Kecskemeti J, Koncz P, Korchagin Y, Kotte R, Kuhn C, Ibnouzahir M, Lebedev A, Maguire C, Manko V V, Mösner J, Montarou G, Montbel I I, Morel P, Neubert W, Pelte D, Rami F, Ramillien V V, Sadchikov A, Seres Z, Sikora B, Smolyankin S, Tezkratt R, Trzaska M, Vasiliev MA, and Wagner P

Published
1995
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29. Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au+Au at E=(100-400)A MeV.

Author

Kotte R, Kämpfer B, Mösner J, Neubert W, Wohlfarth D, Alard JP, Amouroux V V, Basrak Z, Bastid N, Belayev IM, Berger L, Blaich T, Boussange S, Buta A, Caplar R, Cerruti C, Cindro N, Coffin JP, Don R, Dupieux P, Erö J, Fan ZG, Fintz P, Fodor Z, Fraysse L, Freifelder R, Frolov S, Gobbi A, Grigorian Y, Guillaume G, Herrmann N, Hildenbrand KD, Hölbling S, Houari O, Ibnouzahir M, Jeong SC, Jundt F, Kecskemeti J, Koncz P, Korchagin Y, Krämer M, Kuhn C, Legrand I I, Lebedev A, Manko V V, Matulewicz T, Mgebrishvili G, Moisa D, Montarou G, Montbel I I, Pelte D, Petrovici M, Pras P, Rami F, Ramillien V V, Reisdorf W, Sadchikov A, Schüll D, Seres Z, Sikora B, Simion V V, Smolyankin S, Sodan U, and Teh K

Published
1995
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30. Collective motion in selected central collisions of Au on Au at 150A MeV.

Author

Jeong SC, Herrmann N, Fan ZG, Freifelder R, Gobbi A, Hildenbrand KD, Krämer M, Randrup J, Reisdorf W, Schüll D, Sodan U, Teh K, Wessels JP, Pelte D, Trzaska M, Wienold T, Alard JP, Amouroux V V, Basrak Z, Bastid N, Belayev IM, Berger L, Bini M, Blaich T, Boussange S, Buta A, Caplar R, Cerruti C, Cindro N, Coffin JP, Dona R, Dupieux P, Erö J, Fintz P, Fodor Z, Fraysse L, Frolov S, Grigorian Y, Guillaume G, Hölbling S, Houari A, Jundt F, Kecskemeti J, Koncz P, Korchagin Y, Kotte R, Kuhn C, Ibnouzahir M, Legrand I I, Lebedev A, Maguire C, Manko V V, Maurenzig P, Mgebrishvili G, Mösner J, Moisa D, Montarou G, Montbel I I, Morel P, Neubert W, Olmi A, Pasquali G, Petrovici M, and Poggi G

Published
1994
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31. Entropy production in the Au+Au reaction between 150A and 800A MeV.

Author

Kuhn C, Konopka J, Coffin JP, Cerruti C, Fintz P, Guillaume G, Houari A, Jundt F, Maguire CF, Rami F, Tezkratt R, Wagner P, Basrak Z, Caplar R, Cindro N, Hölbling S, Alard JP, Bastid N, Berger L, Boussange S, Belayev IM, Blaich T, Buta A, Don R, Dupieux P, Erö J, Fan ZG, Fodor Z, Freifelder R, Fraysse L, Frolov S, Gobbi A, Grigorian Y, Herrmann N, Hildenbrand KD, Jeong SC, Jorio M, Kecskemeti J, Koncz P, Korchagin Y, Kotte R, Krämer M, Legrand I I, Lebedev A, Manko V V, Matulewicz T, Mgebrishvili G, Mösner J, Moisa D, Montarou G, Montbel I I, Neubert W, Pelte D, Petrovici M, Ramillien S, Reisdorf W, Sadchikov A, Schüll D, Seres Z, Sikora B, Simion V V, Smolyankin S, Sodan U, and Teh KM

Published
1993
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32. Velocity correlations of intermediate mass fragments produced in central collisions of Au+Au at E=150A MeV.

Author

Kämpfer B, Kotte R, Mösner J, Neubert W, Wohlfarth D, Alard JP, Basrak Z, Bastid N, Belayev IM, Blaich T, Buta A, Caplar R, Cerruti C, Cindro N, Coffin JP, Dupieux P, Erö J, Fan ZG, Fintz P, Fodor Z, Freifelder R, Fraysse L, Frolov S, Gobbi A, Grigorian Y, Guillaume G, Herrmann N, Hildenbrand KD, Hölbling S, Houari O, Jeong SC, Jorio M, Jundt F, Kecskemeti J, Koncz P, Korchagin Y, Krämer M, Kuhn C, Legrand I I, Lebedev A, Maguire C, Manko V V, Matulewicz T, Mgebrishvili G, Moisa D, Montaru G, Montbel I I, Morel P, Pelte D, Petrovici M, Rami F, Reisdorf W, Sadchikov A, Schüll D, Seres Z, Sikora B, Simion V V, Smolyankin S, Sodan U, Teh K, Tezkratt R, Trzaska M, Vasiliev MA, and Wagner P

Published
1993
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33. Azimuthal asymmetry of neutral pion emission in Au+Au reactions at 1 GeV/nucleon.

Author

Venema LB, Braak H, Löhner H, Raschke AE, Siemssen RH, Sumbera M, Wilschut HW, Berg F, Kühn W, Metag V V, Notheisen M, Novotny R, Pfeiffer M, Ritman J, Schwalb O, Gobbi A, Hildenbrand KD, Hlavác S, Holzmann R, Simon RS, Sodan U, Teh K, Wessels JP, Herrmann N, Wienold T, Kotte R, Mösner J, Neubert W, Wohlfarth D, Ostendorf R, Schutz Y, Brummund N, and Santo R

Published
1993
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34. Midrapidity source of intermediate-mass fragments in highly central collisions of Au + Au at 150A MeV.

Author

Alard JP, Basrak Z, Bastid N, Belayev IM, Bini M, Blaich T, Bock R, Buta A, Caplar R, Cerruti C, Cindro N, Coffin JP, Crouau M, Dupieux P, Erö J, Fan ZG, Fintz P, Fodor Z, Freifelder R, Fraysse L, Frolov S, Gobbi A, Grigorian Y, Guillaume G, Herrmann N, Hildenbrand KD, Hölbling S, Houari O, Jeong SC, Jorio M, Jundt F, Kecskemeti J, Koncz P, Korchagin Y, Kotte R, Krämer M, Kuhn C, Legrand I I, Lebedev A, Maguire C, Manko V V, Matulewicz T, Mgebrishvili G, Mösner J, Moisa D, Montarou G, Morel P, Neubert W, Olmi A, Pasquali G, Pelte D, Petrovici M, Poggi G, Rami F, Reisdorf W, Sadchikov A, Schüll D, Seres Z, Sikora B, Simion V V, Smolyankin S, Sodan U, Taccetti N, and Teh K

Published
1992
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