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142 results on '"D Pelte"'

1. Wide-acceptance measurement of the K−/K+ ratio from Ni+Ni collisions at 1.91A GeV

Author: Mile Dželalija, M. Korolija, A. Lebedev, Xavier Bernard Lopez, P. Koczon, Ivana Weber, A. Mangiarotti, Ralf Peter Averbeck, M. Merschmeyer, M. Kirejczyk, Anton Andronic, Johann Marton, Valerie Ramillien Barret, K. Wiśniewski, R. Kotte, Pascal Dupieux, A. Reischl, N. Herrmann, K. D. Hildenbrand, Laura Fabbietti, R. H. Munzer, Nicole Bastid, D. Pelte, H. S. Xu, I. E. Yushmanov, V. Simion, A. Le Fèvre, I. M. Deppner, Y. Leifels, Mladen Kiš, K. Suzuki, Jianli Liu, T. I. Kang, M. Berger, W. Reisdorf, Peter Wagner, Piotr Jan Gasik, Paul Buehler, T. Matulewicz, Z. Fodor, Vladislav Manko, Krzysztof Piasecki, Z. Seres, E. Widmann, K. Siwek-Wilczyńska, Mihai Petrovici, Igor Gašparić, O. Czerwiakowa, P. Crochet, Z. Basrak, Fouad Rami, P. Schmidt, J. Kecskemeti, K. S. Sim, A. Zhilin, B. Sikora, Roman Čaplar, Y. Grishkin, Johann Zmeskal, O. N. Hartmann, Byung-Sik Hong, V. Zinyuk, Zhigang Xiao, Michael Cargnelli, Yongsun Kim, M. L. Benabderrahmane, V. T. Smolyankin, M. S. Ryu, A. Schüttauf, Y. H. Zhang, E. Cordier, Gabriel Stoicea, and Z. Tyminski
Subjects: Physics, Meson, 010308 nuclear & particles physics, Plane (geometry), Nuclear Theory, Kinetic energy, 7. Clean energy, 01 natural sciences, Synchrotron, Spectral line, law.invention, Nuclear physics, Distribution (mathematics), law, Yield (chemistry), 0103 physical sciences, High Energy Physics::Experiment, Polar coordinate system, Nuclear Experiment, 010306 general physics
Abstract: The FOPI Collaboration at the GSI SIS-18 synchrotron measured charged kaons from central and semicentral collisions of Ni+Ni at a beam energy of 1.91A GeV. We present the distribution of the K−/K+ ratio on the energy vs polar angle plane in the nucleon-nucleon center-of-mass frame, with and without subtraction of the contribution of ϕ(1020) meson decays to the K− yield. The acceptance of the current experiment is substantially wider compared to the previous measurement of the same colliding system. The ratio of K− to K+ energy spectra is expected to be sensitive to the in-medium modifications of basic kaon properties like mass. Recent results obtained by the HADES Collaboration at 1.23A and 1.76A GeV indicate that after inclusion of the ϕ meson decay contribution to the K− production no difference between the slopes of the K− and K+ energy spectra is observed within uncertainties. For our data a linear fit to this ratio obtained after subtraction of the ϕ meson contribution still shows a decrease with kinetic energy, although a constant value cannot be rejected. The contribution of Λ(1520)→pK− decays estimated from fitting the thermal model to the experimental yields appears to be another factor of moderate relevance.
Published: 2019
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2. Centrality dependence of subthreshold $\phi$ meson production in Ni + Ni collisions at 1.9A GeV

Author: Xavier Bernard Lopez, P. Koczon, Byung-Sik Hong, Anton Andronic, Fouad Rami, Johann Marton, R. Kotte, D. Pelte, O. N. Hartmann, Piotr Jan Gasik, A. Mangiarotti, N. Herrmann, Igor Gašparić, A. Le Fèvre, K. D. Hildenbrand, Y. Leifels, J. Kecskemeti, K. S. Sim, Y. H. Zhang, E. Cordier, Michael Cargnelli, M. Merschmeyer, M. L. Benabderrahmane, E. Widmann, V. Zinyuk, Valerie Ramillien Barret, M. Berger, J. Zmeskal, Gabriel Stoicea, Z. Fodor, I. Weber, B. Sikora, Zhigang Xiao, Z. Seres, A. Reischl, Mihai Petrovici, Laura Fabbietti, Yongsun Kim, Ralf Peter Averbeck, W. Reisdorf, Peter Wagner, Paul Buehler, P. Schmidt, Z. Tyminski, M. Kiš, K. Suzuki, M. Dželalija, P. Crochet, K. Wiśniewski, Pascal Dupieux, T. I. Kang, O. Czerwiakowa, Z. Basrak, Jianli Liu, M. Korolija, I. M. Deppner, A. Lebedev, R. H. Munzer, Nicole Bastid, V. Simion, T. Matulewicz, Krzysztof Piasecki, K. Siwek-Wilczyńska, I. E. Yushmanov, A. Schüttauf, R. Čaplar, M. Kirejczyk, H. S. Xu, Y. Grishkin, V. T. Smolyankin, M. S. Ryu, Vladislav Manko, A. Zhilin, Laboratoire de Physique de Clermont ( LPC ), Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Clermont Auvergne ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Pluridisciplinaire Hubert Curien ( IPHC ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ), FOPI, Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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 Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Particle physics, heavy ion: scattering, Meson, Strangeness, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, K-: production, beam: energy, Nuclear physics, 25.75.Dw, 0103 physical sciences, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Power function, Nuclear Experiment, impact parameter, Physics, energy: kinetic, 010308 nuclear & particles physics, Phi meson, Phi(1020): multiplicity, Phi(1020): production, Exponent, FOPI, High Energy Physics::Experiment, spectrometer, Impact parameter, Centrality, 13.60.Le
Abstract: We analysed the $\phi$ meson production in central Ni+Ni collisions at the beam kinetic energy of 1.93A GeV with the FOPI spectrometer and found the production probability per event of $[8.6 ~\pm~ 1.6 ~(\text{stat}) \pm 1.5 ~(\text{syst})] \times 10^{-4}$. This new data point allows for the first time to inspect the centrality dependence of the subthreshold $\phi$ meson production in heavy-ion collisions. The rise of $\phi$ meson multiplicity per event with mean number of participants can be parameterized by the power function with exponent $\alpha = 1.8 \pm 0.6$. The ratio of $\phi$ to $\text{K}^-$ production yields seems not to depend within the experimental uncertainties on the collision centrality, and the average of measured values was found to be $0.36 \pm 0.05$., Comment: 9 pages, 5 figures
Published: 2016
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3. Shape parameters of the participant source in Ru + Ru collisions at

Author: V. Simion, M. Dželalija, E. Cordier, K. D. Hildenbrand, A. Schuettauf, Gabriel Stoicea, N. Herrmann, V. T. Smolyankin, Philippe Crochet, Z. Tyminski, M. L. Benabderrahmane, Z. Fodor, P. Wagner, A. Gobbi, B. de Schauenburg, Fouad Rami, Igor Gašparić, Y. Leifels, J. Kecskemeti, M. Merschmeyer, Valerie Ramillien Barret, Z. Basrak, I. E. Yushmanov, R. Kotte, D. Pelte, M. R. Stockmeier, D. Wohlfarth, Z. Seres, A. Bendarag, M. Kirejczyk, Nicole Bastid, R. Čaplar, M. M. Smolarkiewicz, Y. Grishkin, Zhigang Xiao, Yongsun Kim, Mihai Petrovici, Byung-Sik Hong, O. N. Hartmann, T. Kress, Alexandre Lebedev, W. Neubert, J. P. Alard, Vladislav Manko, W. Reisdorf, I. J. Soliwoda, A. Mangiarotti, A. Zhilin, Pascal Dupieux, M. Korolija, K. Wiśniewski, P. Koczon, B. Sikora, Xavier Bernard Lopez, Anton Andronic, K. S. Sim, D. Moisa, and K. Siwek-Wilczyńska
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Gaussian, Nuclear Theory, Nuclear physics, Momentum, symbols.namesake, Cross section (physics), Flow (mathematics), Phase space, Isospin, symbols, Impact parameter, Nuclear Experiment
Abstract: New results on nuclear collective flow are presented for central and semi-central Ru + Ru collisions at 400 A MeV measured with the FOPI detector at GSI-Darmstadt. The source shape parameters, flow angle and aspect ratios, are extracted from Gaussian fits to in-plane and out-of-plane momentum distributions. The orientation and the shape of the source exhibit different trends according to the investigated phase space region. The shape parameters of the participant source are studied as a function of the particle mass and collision centrality. The flow angle is found to be independent of the particle mass. Both the flow angle and the aspect ratios depend sensitively on the impact parameter. Detailed comparisons with the predictions of the isospin quantum molecular dynamics model are performed. It is shown in particular that the source shape parameters permit to extract information on the in-medium nucleon–nucleon cross section.
Published: 2004
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4. Sub-threshold φ-meson yield in central collisions

Author: A. Mangiarotti, N. Herrmann, P.R. Maurenzig, A. Gobbi, R. Kotte, J. Kecskemeti, Y. Leifels, J.P. Alard, A. Andronic, R. Averbeck, V. Barret, Z. Basrak, N. Bastid, I. Belyaev, A. Bendarag, G. Berek, R. Čaplar, P. Crochet, A. Devismes, P. Dupieux, M. Dž, Ch. Finck, Z. Fodor, Y. Grishkin, O. Hartmann, K.D. Hildenbrand, B. Hong, Y.J. Kim, M. Kirejczyk, P. Koczoń, M. Korolija, T. Kress, R. Kutsche, A. Lebedev, V. Manko, M. Merschmeyer, D. Moisa, A. Nianine, W. Neubert, D. Pelte, M. Petrovici, C. Plettner, F. Rami, W. Reisdorf, B. de Schauenburg, D. Schü, Z. Seres, B. Sikora, K.S. Sim, V. Simion, K. Siwek-Wilczyń, V. Smolyankin, M. Stockmeier, G. Stoicea, M. Vasiliev, P. Wagner, K. Wiś, D. Wohlfarth, I. Yushmanov, and A. Zhilin
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Background subtraction, Meson, Yield (chemistry), Detector, Production (computer science), Nuclear Experiment, Phi meson, Energy (signal processing)
Abstract: The $\phi$-meson production cross section is measured for the first time at a sub-threshold energy of 1.93 AGeV in \nuc{58}{Ni}+\nuc{58}{Ni} central collisions. The $\phi$ data were obtained within the acceptance of the CDC/Barrel subsystem of FOPI. For a sample of $4.7\cdot 10^6$ central events, after background subtraction, 23 candidates were observed. Extensive GEANT simulations of the detector performance are shown in a thorough comparison to the real response, aiming at a good understanding of the apparatus and at a trustable determination of the efficiencies, production probability and possible systematic errors. A filter procedure is elaborated, which is meant to facilitate the comparison of any theoretical calculation or new data with the current ones. How to extrapolate the present value to a $\phi$-meson cross section in $4\pi$ is also discussed. This result on pseudo-vector mesons can now be compared to existing experimental knowledge for the same reaction at the same incident energy for various outgoing channels, $K^+$ and $K^-$ included. A significant fraction (at least 20%) of the $K^-$-mesons is originating in the decay of the $\phi$, supporting the statement that the two channels are strongly correlated.
Published: 2003
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5. Results from FOPI on strangeness in nuclear matter at SIS energies

Author: M. R. Stockmeier, W. Reisdorf, Kin Sing Stephen Lee, T. Kress, M. Dželalija, A. Somov, V. T. Smolyankin, M. Korolija, R. Kotte, B. de Schauenburg, D. Pelte, G. Berek, A. Devismes, A. Bendarag, K. Siwek-Wilczyńska, R. Čaplar, A. Gobbi, A. Nianine, P. Wagner, Valerie Ramillien Barret, R. Averbeck, D. Moisa, Byung-Sik Hong, K. Wiśniewski, Anton Andronic, Y. Leifels, I. E. Yushmanov, Y. Grishkin, N. Cindro, P. Crochet, Alexandre Lebedev, V. Simion, M. Eskef, W. Neubert, Nicole Bastid, Z. Fodor, N. Herrmann, R. Kutsche, J. P. Alard, D. Schüll, O. Hartmann, Kwang Souk Sim, Pascal Dupieux, B. Sikora, H. Merlitz, F. Rami, M. A. Vasiliev, Z. Basrak, M. Kowalczyk, J. Kecskemeti, I. Belyaev, J. T. Yang, Ch. Finck, Gabriel Stoicea, C. Plettner, Vladislav Manko, M. Kirejczyk, S. Mohren, D. Wohlfarth, A. Zhilin, Yongsun Kim, P Koczon, Z. Seres, Mihai Petrovici, and K.D. Hildenbrand
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Flow (mathematics), Phase space, Nuclear Theory, Detector, High Energy Physics::Experiment, Strangeness, Nuclear Experiment, Nuclear matter
Abstract: Experimental data on charged kaon phase space distributions and strangeness sideward flow measured with the FOPI detector at SIS/GSI are presented. Comparisons are made with the predictions of transport models investigating the in-medium kaon-nucleon potential.
Published: 2001
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6. On the space-time difference of proton and composite particle emission in central heavy-ion reactions at 400 A· MeV

Author: M. Eskef, A. Somov, K. Wiśniewski, R. Kotte, D. Pelte, Y. Leifels, Philippe Crochet, Mihai Petrovici, D. Schüll, N. Cindro, N. Bendarag, Byung-Sik Hong, Alexandre Lebedev, W. Neubert, Nicole Bastid, Pascal Dupieux, Peter Wagner, M. Kowalczyk, D. Wohlfarth, K. S. Lee, T. Kress, J. P. Alard, H. Merlitz, M. Dželalija, Z. Basrak, Y. Yushmanov, Y. Grishkin, D. Moisa, Z. Fodor, W. Reisdorf, A. Gobbi, A. Devismes, V. Simion, B. de Schauenburg, Vladislav Manko, H. W. Barz, Ralf Peter Averbeck, R. Kutsche, A. Zhilin, M. Korolija, J. T. Yang, K. D. Hildenbrand, C. Plettner, R. Čaplar, M. Kirejczyk, Y. J. Kim, Z. Seres, Gabriel Stoicea, M. A. Vasiliev, J. Kecskemeti, A. Nianine, G. Berek, K. Siwek-Wilczyńska, Anton Andronic, K. S. Sim, N. Herrmann, B. Sikora, Fouad Rami, 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, Proton, 010308 nuclear & particles physics, Hadron, Relative velocity, Radius, heavy-ion, correlation function, space-time, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Charged particle, Ion, Nuclear physics, Correlation function (statistical mechanics), 0103 physical sciences, Nuclear fusion, Atomic physics, 010306 general physics
Abstract: Small-angle correlations of pairs of nonidentical light charged particles produced in central collisions of heavy ions in the A= 100 mass region at a beam energy of 400 A· MeV are investigated with the FOPI detector system at GSI Darmstadt. The difference of longitudinal correlation functions with the relative velocity parallel and anti-parallel to the center-of-mass velocity of the pair in the central source frame is studied. This method allows extracting the apparent space-time differences of the emission of the charged particles. Comparing the correlations with results of a final-state interaction model delivers quantitative estimates of these asymmetries. Time delays as short as 1~fm/c or – alternatively – source radius differences of a few tenth fm are resolved. The strong collective expansion of the participant zone introduces not only an apparent reduction of the source radius but also a modification of the emission times. After correcting for both effects a complete sequence of the space-time emission of p, d, t, 3He, α particles is presented for the first time.
Published: 1999
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7. The Coulomb interaction between pion wavepackets: the pi+-pi- puzzle

Author: H. Merlitz and D. Pelte
Subjects: Physics, Momentum, Nuclear and High Energy Physics, Pion, Correlation function, Wave packet, Quantum electrodynamics, Plane wave, Coulomb, Positive correlation, Signal
Abstract: The time dependent Schr\"odinger equation for $\pi^+$--$\pi^-$ pairs, which are emitted from the interaction zone in relativistic nuclear collisions, is solved using wavepacket states. It is shown that the Coulomb enhancement in the momentum correlation function of such pairs is smaller than obtained in earlier calculations based on Coulomb distorted plane waves. These results suggest that the experimentally observed positive correlation signal cannot be caused by the Coulomb interaction between pions emitted from the interaction zone. But other processes which involve long-lived resonances and the related extended source dimensions could provide a possible explanation for the observed signal.
Published: 1999
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8. Identification of baryon resonances in central heavy-ion collisions at energies between 1 and 2 AGeV

Author: M. Eskef, D. Pelte, G. Goebels, E. Häfele, N. Herrmann, M. Korolija, Y. Leifels, H. Merlitz, S. Mohren, M.R. Stockmeier, M. Trzaska, J.P. Alard, A. Andronic, R. Averbeck, Z. Basrak, N. Bastid, I. Belyaev, D. Best, A. Buta, R. Čaplar, N. Cindro, J.P. Coffin, P. Crochet, P. Dupieux, M. Dželalija, L. Fraysse, Z. Fodor, A. Genoux-Lubain, A. Gobbi, K.D. Hildenbrand, B. Hong, F. Jundt, J. Kecskemeti, M. Kirejczyk, R. Kotte, R. Kutsche, A. Lebedev, V. Manko, J. Mösner, D. Moisa, W. Neubert, M. Petrovici, C. Pinkenburg, C. Plettner, P. Pras, F. Rami, V. Ramillien, W. Reisdorf, J.L. Ritman, B. de Schauenburg, D. Schüll, Z. Seres, B. Sikora, V. Simion, K. Siwek-Wilczynska, V. Smolyankin, M.A. Vasiliev, P. Wagner, G.S. Wang, K. Wisniewski, D. Wohlfarth, and A. Zhilin
Subjects: Physics, Nuclear and High Energy Physics, Mass distribution, 010308 nuclear & particles physics, Resonance, Kinetic energy, 7. Clean energy, 01 natural sciences, Spectral line, Baryon, Nuclear physics, Pion, Isospin, 0103 physical sciences, Invariant (mathematics), Nuclear Experiment, 010306 general physics
Abstract: The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the $p_t$ spectra of charged pions by a method which does not depend on a specific resonance shape. In addition the mass distributions of resonances are obtained from the invariant masses of $(p, \pi^{\pm})$ pairs. With both methods the deduced mass distributions are shifted by an average value of -60 MeV/c$^2$ relative to the mass distribution of the free $\Delta(1232)$ resonance, the distributions descent almost exponentially towards mass values of 2000 MeV/c^2. The observed differences between $(p, \pi^-)$ and $(p, \pi^+)$ pairs indicate a contribution of isospin $I = 1/2$ resonances. The attempt to consistently describe the deduced mass distributions and the reconstructed kinetic energy spectra of the resonances leads to new insights about the freeze out conditions, i.e. to rather low temperatures and large expansion velocities.
Published: 1998
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9. 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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10. 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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11. 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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12. 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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13. 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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14. Analysis of the sequential fission observed in collisions of100Mo +100Mo and120Sn +120Sn around 20 A�MeV

Author: P. R. Maurenzig, A. Péghaire, U. Jahnke, G. Rudolf, A. Gobbi, Alessandro Olmi, Giovanni Casini, Andrea Stefanini, D. Guerreau, D. Pelte, B. Bilwes, M. Petrovici, K. D. Hildenbrand, H. Stelzer, J. Galin, N. Herrmann, R. Bilwes, J.C. Adloff, R. Freifelder, R. J. Charity, F. Rami, M. Gnirs, and J. P. Wessels
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Mass asymmetry, Fission, Phase (matter), Relative velocity, Nuclear fusion, Non-equilibrium thermodynamics, Atomic physics, Coincidence
Abstract: Events with 2, 3 and 4 heavy fragments (A≥20) detected in the reactions100Mo +100Mo at 18.7, 23.7 A·MeV and120Sn +120Sn at 18.4 A·MeV were analyzed by means of an improved version of the kinematic coincidence method. The phase-space distributions prove that 3- (and possibly 4-) body events predominantly originate from a two-step mechanism and are compatible with the hypothesis of a binary deep-inelastic interaction followed by the further fissionlike decay of one (or both) of the primary fragments. The characteristics of the fission step — mass asymmetry, relative velocity, in-plane and out-of-plane angles — have been reconstructed for the 3-body events and indications are found that nonequilibrium effects at the end of the deep-inelastic phase may influence the fissionlike decay.
Published: 1995
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15. Quantum correlations of bosons and fermions produced in heavy ion collisions

Author: H. Merlitz and D. Pelte
Subjects: Condensed Matter::Quantum Gases, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Monte Carlo method, Nuclear fusion, Diffusion Monte Carlo, Fermion, Statistical mechanics, Quantum, Boson
Abstract: A quantum statistical approach to simulate Bose-Einstein correlations of many boson systems is presented. The extension to fermions and Coulomb-interacting bosons is discussed. This approach appears to be very efficient and is applicable also to cases with very high multiplicities. A technique to analyze pion correlations via their counting distributions is developed. The exact counting distributions for bosons as well as for fermions are derived. The problem of incomplete data occuring in detectors with an acceptance angleΩ < 4π is studied. The application to Monte Carlo generated pion distributions show that this technique offers a valuable supplement to the usual Hanbury-Brown, Twiss method.
Published: 1995
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16. 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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17. 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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18. Multifragment events in the reactionNi58+27Al at 15.8 MeV/nucleon

Author: R. W. Novotny, Volker Metag, Dan Shapira, D. Rentsch, and D. Pelte
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Fission, Nuclear Theory, Momentum transfer, Inelastic scattering, Deep inelastic scattering, Breakup, Nuclear physics, Excited state, Atomic physics, Nuclear Experiment, Nucleon
Abstract: Intermediate mass fragment (IMF) production was studied in the inverse kinematics reaction [sup 58]Ni+[sup 27]Al at 15.8 MeV/nucleon bombarding energy using the Heavy Ion Light Ion (HILI) detector. Exit channels with up to 4 IMFs have been observed. The three-body events can be ascribed to different production mechanisms: (i) incomplete momentum transfer with projectile spectator breakup, (ii) sequential fission following a deep inelastic reaction, and (iii) fast sequential fission (i.e., with Coulomb final-state interaction) in competition with a prompt breakup out of a toroidal configuration. The identified ternary reaction mechanisms, covering an extremely wide dynamic range, could be observed simultaneously; a subgroup of events is compatible with an instantaneous breakup of a highly excited nuclear system.
Published: 1993
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19. 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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20. 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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21. 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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22. Measurement ofK*(892)0andK0mesons inAl+Alcollisions at 1.9AGeV

Author: Y. Grishkin, Byung-Sik Hong, Z. Seres, J. Zmeskal, Mihai Petrovici, R. Kotte, D. Pelte, Z. Fodor, W. Neubert, Z. Tyminski, M. Dželalija, M. Korolija, Piotr Jan Gasik, Z. Basrak, Johann Marton, Nicole Bastid, A. Schüttauf, P. Crochet, A. Lebedev, Igor Gašparić, Peter Wagner, Paul Buehler, Laura Fabbietti, J. Kecskemeti, R. Čaplar, Vladislav Manko, M. L. Benabderrahmane, W. Reisdorf, Krzysztof Piasecki, M. Merschmeyer, O. N. Hartmann, Valerie Ramillien Barret, V. T. Smolyankin, M. S. Ryu, A. Zhilin, Xiang Yang Zhang, K. Siwek-Wilczyńska, Paul Kienle, Michael Cargnelli, Y. Leifels, Pascal Dupieux, Xavier Bernard Lopez, P. Koczon, K. S. Sim, I. Fijał-Kirejczyk, Zhigang Xiao, Anton Andronic, T. Yamazaki, Yongsun Kim, M. Kirejczyk, Fouad Rami, M. Kiš, I. E. Yushmanov, V. Simion, E. Widmann, T. Matulewicz, B. Sikora, K. Suzuki, N. Herrmann, K. D. Hildenbrand, T. I. Kang, K. Wiśniewski, and P. Schmidt
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Model prediction, 0103 physical sciences, Yield ratio, Production (computer science), 010306 general physics, 01 natural sciences
Abstract: A new measurement of subthreshold ${K}^{*}(892){}^{0}$ and ${K}^{0}$ production is presented. The experimental data complete the measurement of strange particles produced in $\mathrm{Al}+\mathrm{Al}$ collisions at 1.9$A$ GeV measured with the FOPI detector at SIS at GSI (Darmstadt). The ${K}^{*}(892){}^{0}/{K}^{0}$ yield ratio is found to be $0.0315\ifmmode\pm\else\textpm\fi{}0.006(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.012(\mathrm{syst}.)$ and is in good agreement with the transport model prediction. These measurements provide information on the in-medium cross section of ${K}^{+}$-${\ensuremath{\pi}}^{\ensuremath{-}}$ fusion, which is the dominant process in subthreshold ${K}^{*}(892){}^{0}$ production.
Published: 2010
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23. 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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24. Excitation of the? (1232)-resonance in proton-nucleus collisions

Author: M.C. Lemaire, J.C. Jourdain, J. L. Boyard, M. Trzaska, Jacques Vandermeulen, T. Hennino, A. Rahmani, B. Ramstein, P. Zupranski, J. Augerat, Gerard Montarou, P. Radvanyi, J. P. Alard, Nicole Bastid, Pascal Dupieux, Ph. Gorodetzky, O. Valette, Joseph Cugnon, M.J. Parizet, B. Lucas, D. Bachelier, C. Cavata, M. Roy-Stephan, J. Gosset, A. LeMerdy, D. Pelte, J. Marroncle, J. Poitou, D. L'Hôte, P. Charmensat, and D. Quassoud
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Pion, Proton, Scattering, Resonance, Nuclear fusion, Invariant mass, Atomic physics, Nuclear Experiment, Nuclear matter, Excitation
Abstract: The excitation of theΔ resonance is observed in proton collisions on C, Nb and Pb targets at 0.8 and 1.6 GeV incident energies. The mass E0 and widthΓ of the resonance are determined from the invariant mass spectra of correlated (p, π±)-pairs in the final state of the collision: The mass E0 is smaller than that of the free resonance, however by comparing to intra-nuclear cascade calculations, this reduction is traced back to the effects of Fermi motion, NN scattering and pion reabsorption in nuclear matter.
Published: 1991
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25. Subthreshold production ofΣ(1385)baryons in Al+Al collisions at1.9AGeV

Author: Johann Marton, X. Lopez, Byung-Sik Hong, P. Wagner, Igor Gašparić, J. Kecskemeti, R. Kotte, D. Pelte, Philippe Crochet, W. Neubert, Z. Basrak, M. Merschmeyer, T. I. Kang, Z. Seres, K. Siwek-Wilczyńska, N. Herrmann, Valerie Ramillien Barret, Paul Kienle, Y. J. Kim, V. Simion, K. S. Sim, M. Dzelalija, J. Zmeskal, Eberhard Widmann, D. Wohlfarth, E. Cordier, Mihai Petrovici, A. Schüttauf, O. N. Hartmann, Y. Grishkin, Y. Leifels, M. L. Benabderrahmane, Z. Fodor, T. Matulewicz, Fouad Rami, Michael Cargnelli, Gabriel Stoicea, Paul Buehler, M. Kiš, P. Schmidt, Laura Fabbietti, K. D. Hildenbrand, Vladislav Manko, Pascal Dupieux, Z. Tyminski, W. Reisdorf, I. E. Yushmanov, R. Čaplar, Zhigang Xiao, A. Zhilin, Anton Andronic, Xiang Yang Zhang, T. Yamazaki, K. Wiśniewski, P. Koczon, V. T. Smolyankin, M. S. Ryu, K. Suzuki, B. Sikora, A. Lebedev, Krzysztof Piasecki, M. Korolija, M. Kirejczyk, and Nicole Bastid
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Subthreshold conduction, Nuclear Theory, Sigma, Strangeness production, Strangeness, Lambda, 01 natural sciences, Particle identification, Sigma baryon, Baryon, Nuclear physics, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: First measurement of subthreshold {sigma}(1385) production is presented. Experimental data are presented for Al+Al reactions at 1.9A GeV measured with the FOPI detector at SIS/GSI. The {sigma}(1385)/{lambda} ratio is found to be in good agreement with the transport and statistical model predictions. The results allow for a better understanding of subthreshold strangeness production and strangeness exchange reaction which is the dominant process for K{sup -} production below and close-to threshold.
Published: 2007
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26. Isospin dependence of relative yields ofK+andK0mesons at 1.528AGeV

Author: Z. Fodor, Z. Tyminski, X. Lopez, Nicole Bastid, M. Kiš, Igor Gašparić, J. Kecskemeti, Z. Basrak, N. Herrmann, Y. J. Kim, K. S. Sim, R. Kotte, D. Pelte, Philippe Crochet, Peter Wagner, M. Merschmeyer, Y. Grishkin, Zhigang Xiao, Valerie Ramillien Barret, R. Čaplar, G. Ferini, M. Dželalija, A. Lebedev, Pascal Dupieux, B. Sikora, Xiang Yang Zhang, A. Zhilin, Y. Leifels, E. Cordier, V. T. Smolyankin, T. I. Kang, Fouad Rami, I. E. Yushmanov, M. Kirejczyk, M. L. Benabderrahmane, M. S. Ryu, D. Wohlfarth, Z. Seres, Gabriel Stoicea, M. Korolija, K. D. Hildenbrand, A. Schüttauf, V. Simion, K. Wiśniewski, P. Koczon, Anton Andronic, Byung-Sik Hong, Theodoros Gaitanos, W. Neubert, K. Siwek-Wilczyńska, W. Reisdorf, Mihai Petrovici, and O. N. Hartmann
Subjects: Mass number, Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Nuclear matter, Kinetic energy, 7. Clean energy, 01 natural sciences, Nuclear physics, Mean field theory, Isospin, 0103 physical sciences, Sensitivity (control systems), Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract: Results on $K^+$ and $K^0$ meson production in $^{96}_{44}$Ru + $^{96}_{44}$Ru and $^{96}_{40}$Zr + $^{96}_{40}$Zr collisions at a beam kinetic energy of 1.528$A$ GeV, measured with the FOPI detector at GSI-Darmstadt, are investigated as a possible probe of isospin effects in high density nuclear matter. The measured double ratio ($K^+/K^0$)$_{Ru}$/($K^+/K^0$)$_{Zr}$ is compared to the predictions of a thermal model and a Relativistic Mean Field transport model using two different collision scenarios and under different assumptions on the stiffness of the symmetry energy. We find a good agreement with the thermal model prediction and the assumption of a soft symmetry energy for infinite nuclear matter while more realistic transport simulations of the collisions show a similar agreement with the data but also exhibit a reduced sensitivity to the symmetry term.
Published: 2007
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27. K0 and Lambda production in Ni+Ni collisions near threshold

Author: A. Schüttauf, M. Korolija, V. Simion, A. Zhilin, T. I. Kang, K. S. Sim, T. Matulewicz, Anton Andronic, Y. Grishkin, W. Reisdorf, Z. G. Xiao, X. Lopez, Z. Seres, Xiang Yang Zhang, M. Merschmeyer, R. Čaplar, M. L. Benabderrahmane, Valerie Ramillien Barret, I. E. Yushmanov, V. T. Smolyankin, M. S. Ryu, Z. Tyminski, M. Dželalija, H. S. Xu, Philippe Crochet, Fouad Rami, Yongsun Kim, B. Sikora, Mihai Petrovici, O. N. Hartmann, K. Siwek-Wilczyńska, E. Cordier, R. Kotte, Byung-Sik Hong, Y. Leifels, D. Pelte, A. Mangiarotti, M. Kiš, Gabriel Stoicea, Nicole Bastid, Igor Gašparić, J. Kecskemeti, K. D. Hildenbrand, M. Kirejczyk, N. Herrmann, K. Wiśniewski, Z. Fodor, P. Koczon, A. Lebedev, Z. Basrak, Pascal Dupieux, 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), Département Recherches Subatomiques (DRS-IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and FOPI
Subjects: Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Nuclear Theory, Strangeness, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Lambda baryon, Lambda, 01 natural sciences, 7. Clean energy, Nuclear physics, Phase space, Yield (chemistry), 25.75.Dw, 0103 physical sciences, heavy-ions, kaons, strangeness, threshold energies, Rapidity, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment
Abstract: New results concerning the production of neutral strange particles, $K^0$ and $\Lambda$ in Ni + Ni collisions at 1.93$A$ GeV, measured with the FOPI detector at GSI-Darmstadt, are presented. Rapidity density distributions and Boltzmann slope parameter distributions are measured in nearly the full phase space of the reaction. The observables are compared to existing $K^+$ and proton data. While the $K^0$ data agree with previously reported $K^+$ measurements, the $\Lambda$ distributions show a different behavior relative to that of protons. The strangeness balance and the production yield per participating nucleon as a function of the centrality of the reaction are discussed, for the first time at SIS energies., Comment: 10 pages, 8 figures
Published: 2007
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28. Charged pion production in4496Ru+4496Rucollisions at400Aand1528AMeV

Author: D. Wohlfarth, A. Gobbi, Z. Fodor, M. R. Stockmeier, A. Zhilin, Zhigang Xiao, Z. Basrak, Y. Grishkin, K. S. Sim, V. Simion, T. Kress, Yongsun Kim, Byung-Sik Hong, Nicole Bastid, W. Reisdorf, A. Lebedev, A. Schüttauf, Y. Leifels, P. Crochet, W. Neubert, K. Wiśniewski, Pascal Dupieux, A. Mangiarotti, P. Koczon, R. Čaplar, M. Korolija, Z. Seres, M. Dželalija, R. Kotte, D. Pelte, V. T. Smolyankin, Mihai Petrovici, O. N. Hartmann, M. Kirejczyk, I. E. Yushmanov, M. L. Benabderrahmane, Peter Wagner, J. Kecskemeti, M. Merschmeyer, Valerie Ramillien Barret, N. Herrmann, K. D. Hildenbrand, Gabriel Stoicea, Z. Tyminski, K. Siwek-Wilczyńska, Xavier Bernard Lopez, Anton Andronic, B. Sikora, and Fouad Rami
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Pion, 010308 nuclear & particles physics, Nuclear Theory, 0103 physical sciences, Production (economics), Nuclear Experiment, 010306 general physics, 01 natural sciences
Published: 2005
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29. First analysis of anisotropic flow with Lee--Yang zeroes

Author: Mihai Petrovici, O. N. Hartmann, Nicolas Borghini, P. Koczon, M. L. Benabderrahmane, Vladislav Manko, Byung-Sik Hong, N. Herrmann, W. Neubert, I. Gapari, M. M. Smolarkiewicz, B. Sikora, K. Siwek-Wilczyska, I. J. Soliwoda, Philippe Crochet, A. Zhilin, A. Mangiarotti, K. D. Hildenbrand, Nicole Bastid, A. Schuettauf, W. Reisdorf, Y. Grishkin, Xavier Bernard Lopez, A. Lebedev, Anton Andronic, D. Moisa, M. Merschmeyer, V. Simion, Valerie Ramillien Barret, Y. Leifels, Zhigang Xiao, Yongsun Kim, Z. Fodor, A. Gobbi, M. Dbeelalija, Fouad Rami, M. R. Stockmeier, M. Kirejczyk, V. T. Smolyankin, Z. Tyminski, I. E. Yushmanov, D. Wohlfarth, J. Kecskemeti, K. S. Sim, R. Kotte, D. Pelte, E. Cordier, Gabriel Stoicea, K. Winiewski, M. Korolija, R. Čaplar, Pascal Dupieux, Z. Basrak, Jean-Yves Ollitrault, Z. Seres, T. Kress, 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, Elliptic flow, Detector, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Azimuth, 0103 physical sciences, 25.70.-z, 25.75.Ld, Order (group theory), Nuclear Experiment (nucl-ex), 010306 general physics, Anisotropy, Nucleon, Nuclear Experiment, Cumulant, Energy (signal processing)
Abstract: We report on the first analysis of directed and elliptic flow with the new method of Lee--Yang zeroes. Experimental data are presented for Ru+Ru reactions at 1.69 AGeV measured with the FOPI detector at SIS/GSI. The results obtained with several methods, based on the event-plane reconstruction, on Lee--Yang zeroes, and on multi-particle cumulants (up to 5th order) applied for the first time at SIS energies, are compared. They show conclusive evidence that azimuthal correlations between nucleons and composite particles at this energy are largely dominated by anisotropic flow., Comment: 5 pages, 3 figures, submitted to Phys. Rev. C Rapid Com
Published: 2005
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30. Two-proton small-angle correlations in central heavy-ion collisions: a beam-energy and system-size dependent study

Author: R. Kotte, J. P. Alard, A. Andronic, V. Barret, Z. Basrak, N. Bastid, M. L. Benabderrahmane, R. Čaplar, E. Cordier, P. Crochet, P. Dupieux, M. Dželalija, Z. Fodor, I. Gašparić, A. Gobbi, Y. Grishkin, O. N. Hartmann, N. Herrmann, K. D. Hildenbrand, B. Hong, J. Kecskemeti, Y. J. Kim, M. Kirejczyk, P. Koczon, M. Korolija, T. Kress, A. Lebedev, Y. Leifels, X. Lopez, M. Merschmeyer, J. Mösner, W. Neubert, D. Pelte, M. Petrovici, F. Rami, W. Reisdorf, B. de Schauenburg, A. Schüttauf, Z. Seres, B. Sikora, K. S. Sim, V. Simion, K. Siwek-Wilczyńska, V. Smolyankin, G. Stoicea, Z. Tyminski, P. Wagner, K. Wiśniewski, D. Wohlfarth, Z. G. Xiao, Y. Yushmanov, A. Zhilin, 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 and High Energy Physics, Equation of state, Proton, Gaussian, 25.70.Pq - Multifragment emission and correlations, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, symbols.namesake, 0103 physical sciences, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), 010308 nuclear & particles physics, Interaction model, proton-proton correlations, relativistic nuclear collisions, intermediate-mass fragments, intensity interferometry, velocity correlations, pion spectra, Correlation function (statistical mechanics), symbols, Physics::Accelerator Physics, Nucleon, Beam (structure)
Abstract: Small-angle correlations of pairs of protons emitted in central collisions of Ca + Ca, Ru + Ru and Au + Au at beam energies from 400 to 1500 MeV per nucleon are investigated with the FOPI detector system at SIS/GSI Darmstadt. Dependences on system size and beam energy are presented which extend the experimental data basis of pp correlations in the SIS energy range substantially. The size of the proton-emitting source is estimated by comparing the experimental data with the output of a final-state interaction model which utilizes either static Gaussian sources or the one-body phase-space distribution of protons provided by the BUU transport approach. The trends in the experimental data, i.e. system-size and beam energy dependences, are well reproduced by this hybrid model. However, the pp correlation function is found rather insensitive to the stiffness of the equation of state entering the transport model calculations., 9 pages, 8 figures, accepted at Eur. Phys. Journ. A
Published: 2005
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31. Excitation function of elliptic flow in Au+Au collisions and the nuclear matter equation of state

Author: Xavier Bernard Lopez, Anton Andronic, N. Herrmann, B. Sikora, L. Benabderrahmane, Z. Seres, K. Wiśniewski, A. Mangiarotti, Philippe Crochet, K. S. Sim, E. Cordier, R. Čaplar, Igor Gašparić, M. Kirejczyk, A. Zhilin, J. Kecskemeti, M. R. Stockmeier, Gabriel Stoicea, W. Reisdorf, M. Merschmeyer, Valerie Ramillien Barret, V. Simion, Mihai Petrovici, O. N. Hartmann, M. Dželalija, T. Kress, Fouad Rami, Y. Leifels, D. Wohlfarth, Pascal Dupieux, P. Koczon, V. T. Smolyankin, B. de Schauenburg, G. Berek, Nicole Bastid, Zhigang Xiao, K. Siwek-Wilczyńska, Byung-Sik Hong, Yongsun Kim, A. Lebedev, A. Schüttauf, W. Neubert, Z. Basrak, Z. Tyminski, I. E. Yushmanov, Y. Grishkin, K. D. Hildenbrand, M. Korolija, Z. Fodor, P. Wagner, R. Kotte, D. Pelte, 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: Excitation function, Physics, Nuclear and High Energy Physics, Equation of state, Range (particle radiation), 010308 nuclear & particles physics, Elliptic flow, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, 01 natural sciences, Nuclear physics, Flow (mathematics), 0103 physical sciences, Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Nuclear Experiment, Scaling
Abstract: We present measurements of the excitation function of elliptic flow at midrapidity in Au+Au collisions at beam energies from 0.09 to 1.49 GeV per nucleon. For the integral flow, we discuss the interplay between collective expansion and spectator shadowing for three centrality classes. A complete excitation function of transverse momentum dependence of elliptic flow is presented for the first time in this energy range, revealing a rapid change with incident energy below 0.4 AGeV, followed by an almost perfect scaling at the higher energies. The equation of state of compressed nuclear matter is addressed through comparisons to microscopic transport model calculations., Comment: 10 pages, 4 eps figures, submitted for publication. Data files will be available at http://www.gsi.de/~fopiwww/pub/
Published: 2005
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32. Nuclear Stopping from0.09Ato1.93A GeVand Its Correlation to Flow

Author: Philippe Crochet, V. Simion, Y. Leifels, Mihai Petrovici, O. N. Hartmann, Z. Fodor, K. Wisniewski, A. Gobbi, R. Čaplar, A. Schüttauf, Pascal Dupieux, Fouad Rami, I. E. Yushmanov, Xavier Bernard Lopez, K. S. Sim, P. Wagner, J. Mösner, J. P. Alard, Z. Seres, M. Merschmeyer, M. L. Benabderrahmane, R. Kotte, M. Dželalija, D. Pelte, Anton Andronic, M. Korolija, V. T. Smolyankin, Y. Grishkin, Byung-Sik Hong, Valerie Ramillien Barret, T. Kress, Z. Basrak, W. Neubert, K. Siwek-Wilczyńska, N. Herrmann, B. Sikora, Zhigang Xiao, Yongsun Kim, J. Kecskemeti, M. Kirejczyk, A. Zhilin, Nicole Bastid, Gabriel Stoicea, Z. Tyminski, P. Koczon, A. Lebedev, M. R. Stockmeier, D. Wohlfarth, K. D. Hildenbrand, W. Reisdorf, and B. de Schauenburg
Subjects: Nuclear physics, Physics, General Physics and Astronomy, Heavy ion, Nuclear Experiment, Excitation
Abstract: We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between $0.09A$ and $1.93A\text{ }\text{ }\mathrm{GeV}$. For the heaviest system, $\mathrm{Au}+\mathrm{Au}$, we observe a plateau of maximal stopping extending from about $0.2A$ to $0.8A\text{ }\text{ }\mathrm{GeV}$ with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.
Published: 2004
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33. Azimuthal dependence of collective expansion for symmetric heavy-ion collisions

Author: Xavier Bernard Lopez, Anton Andronic, M. Kirejczyk, Valerie Ramillien Barret, N. Herrmann, D. Wohlfarth, Z. Seres, B. Sikora, Gabriel Stoicea, V. Simion, J. P. Alard, M. Dželalija, V. T. Smolyankin, Yongsun Kim, Pawel Danielewicz, Nicole Bastid, T. Kress, K. S. Sim, J. Kecskemeti, R. Kotte, D. Pelte, Y. Leifels, M. R. Stockmeier, A. Zhilin, K. Wiśniewski, K. Siwek-Wilczyńska, M. Merschmeier, K. D. Hildenbrand, R. Čaplar, Mihai Petrovici, O. N. Hartmann, W. Reisdorf, I. E. Yushmanov, D. Schüll, Byung-Sik Hong, P. Crochet, W. Neubert, M. Korolija, Z. Fodor, Fouad Rami, Z. Basrak, A. Lebedev, Pascal Dupieux, 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, 010308 nuclear & particles physics, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Function (mathematics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Azimuth, Transverse plane, Flow (mathematics), 0103 physical sciences, Heavy ion, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, 010306 general physics, Centrality, Nucleon, Energy (signal processing)
Abstract: Detailed studies of the azimuthal dependence of the mean fragment and flow energies in the Au+Au and Xe+CsI systems are reported as a function of incident energy and centrality. Comparisons between data and model calculations show that the flow energy values along different azimuthal directions could be viewed as snapshots of the fireball expansion with different exposure times. For the same number of participating nucleons more transversally elongated participant shapes from the heavier system produce less collective transverse energy. Good agreement with BUU calculations is obtained for a soft nuclear equation of state., Comment: 4 pages, 4 figures, accepted at Phys. Rev. Lett
Published: 2003

34. Directed flow in Au+Au, Xe+CsI and Ni+Ni collisions and the nuclear equation of state

Author: M. Merschmeyer, Valerie Ramillien Barret, V. Simion, M. R. Stockmeier, P. Wagner, Xavier Bernard Lopez, R. Kotte, D. Pelte, P. Crochet, B. de Schauenburg, Anton Andronic, Y. Grishkin, A. Zhilin, Z. Tyminski, T. Kress, M. Dželalija, N. Herrmann, Ch. Finck, K. Wiśniewski, P. Koczon, B. Sikora, V. T. Smolyankin, R. Čaplar, J. Kecskemeti, Mihai Petrovici, Byung-Sik Hong, J. P. Alard, W. Reisdorf, Nicole Bastid, O. N. Hartmann, Alexandre Lebedev, Z. Seres, A. Schüttauf, Z. Fodor, W. Neubert, I. E. Yushmanov, K. D. Hildenbrand, A. Gobbi, D. Wohlfarth, Gabriel Stoicea, Fouad Rami, M. Korolija, G. Berek, Yongsun Kim, Y. Leifels, K. Siwek-Wilczyńska, Pascal Dupieux, M. Kirejczyk, Z. Basrak, A. Devismes, and K. S. Sim
Subjects: Physics, Nuclear and High Energy Physics, Equation of state, Nuclear Theory, FOS: Physical sciences, Charge (physics), Nuclear equation of state, heavy-ion collisions, plus au collisions, momentum-dependent interactions, collective-flow, sideward flow, transverse flow, fragment flow, isospin dependence, mass dependence, balance energy, Nuclear matter, Momentum, Nuclear physics, Flow (mathematics), Isospin, Rapidity, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment
Abstract: We present new experimental data on directed flow in collisions of Au+Au, Xe+CsI and Ni+Ni at incident energies from 90 to 400A MeV. We study the centrality and system dependence of integral and differential directed flow for particles selected according to charge. All the features of the experimental data are compared with Isospin Quantum Molecular Dynamics (IQMD) model calculations in an attempt to extract information about the nuclear matter equation of state (EoS). We show that the combination of rapidity and transverse momentum analysis of directed flow allow to disentangle various parametrizations in the model. At 400A MeV, a soft EoS with momentum dependent interactions is best suited to explain the experimental data in Au+Au and Xe+CsI, but in case of Ni+Ni the model underpredicts flow for any EoS. At 90A MeV incident beam energy, none of the IQMD parametrizations studied here is able to consistently explain the experimental data., RevTeX, 20 pages, 30 eps figures, accepted for publication in Phys. Rev. C. Data files available at http://www.gsi.de/~fopiwww/pub/
Published: 2003

35. Proton and deuteron rapidity distributions and nuclear stopping in96Ru(96Zr)+96Ru(96Zr)collisions at400AMeV

Author: T. Kress, X. Lopez, Byung-Sik Hong, R. Čaplar, D. H. Kang, V. Simion, W. Neubert, R. Kutsche, G. Berek, P. Dupieux, A. Andronic, C. Finck, A. Devismes, K. Siwek-Wilczyńska, N. Herrmann, P. Crochet, D. Schűll, M. Kirejczyk, V. Barret, K. D. Hildenbrand, A. Lebedev, M. Dželalija, N. Bastid, J. Kecskemeti, Y. Leifels, P. Koczon, A. Gobbi, Y. Grishkin, D. Pelte, Z. Basrak, K. Wiśniewski, M. R. Stockmeier, D. Wohlfarth, W. Reisdorf, Z. Fodor, B. de Schauenburg, O. N. Hartmann, I. E. Yushmanov, Yongsun Kim, B. Sikora, A. Zhilin, J. P. Alard, K. S. Sim, R. Kotte, G. Stoicea, M. Petrovici, M. Korolija, P. Wagner, Z. Seres, V. Smolyankin, and F. Rami
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Proton, Deuterium, Rapidity
Published: 2002
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36. Differential Directed Flow in Au+Au Collisions

Author: A. Devismes, N. Herrmann, Peter Wagner, Z. Basrak, Valerie Ramillien Barret, T. Kress, B. Sikora, D. Wohlfarth, K. Wiśniewski, Mihai Petrovici, G. Berek, O. N. Hartmann, A. Bendarag, K. Siwek-Wilczyńska, Fouad Rami, Y. Leifels, Yongsun Kim, Byung-Sik Hong, M. Dželalija, Alexandre Lebedev, Ch. Finck, Nicole Bastid, P. Koczon, W. Neubert, W. Reisdorf, R. Kotte, Z. Seres, J. Kecskemeti, D. Pelte, A. Zhilin, Anton Andronic, R. Kutsche, B. de Schauenburg, R. Čaplar, J. P. Alard, Gabriel Stoicea, I. E. Yushmanov, V. T. Smolyankin, V. Simion, K. D. Hildenbrand, Y. Grishkin, M. Kirejczyk, Z. Fodor, Pascal Dupieux, D. Schüll, P. Crochet, M. R. Stockmeier, M. Korolija, K. S. Sim, and A. Gobbi
Subjects: Physics, Nuclear and High Energy Physics, FOS: Physical sciences, Function (mathematics), Nuclear matter, Flow (mathematics), Domain (ring theory), Particle, Rapidity, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, Fourier series, pacs:25.75.Ld, Energy (signal processing)
Abstract: We present experimental data on directed flow in semi-central Au+Au collisions at incident energies from 90 to 400 A MeV. For the first time for this energy domain, the data are presented in a transverse momentum differential way. We study the first order Fourier coefficient v1 for different particle species and establish a gradual change of its patterns as a function of incident energy and for different regions in rapidity., 5 pages, Latex, 5 eps figures, accepted for publication in Phys. Rev. C (Rapid Communications). Data files available at http://www-linux.gsi.de/~andronic/fopi/v1.html
Published: 2001

37. Transition from in-plane to out-of-plane azimuthal enhancement in Au+Au collisions

Author: A Andronic, G Stoicea, M Petrovici, V Simion, P Crochet, J.P Alard, R Averbeck, V Barret, Z Basrak, N Bastid, A Bendarag, G Berek, R Čaplar, A Devismes, P Dupieux, M Dželalija, M Eskef, Ch Finck, Z Fodor, A Gobbi, Y Grishkin, O.N Hartmann, N Herrmann, K.D Hildenbrand, B Hong, J Kecskemeti, Y.J Kim, M Kirejczyk, M Korolija, R Kotte, T Kress, R Kutsche, A Lebedev, K.S Lee, Y Leifels, V Manko, H Merlitz, W Neubert, D Pelte, C Plettner, F Rami, W Reisdorf, B de Schauenburg, D Schüll, Z Seres, B Sikora, K.S Sim, K Siwek-Wilczyńska, V Smolyankin, M.R Stockmeier, M Vasiliev, P Wagner, K Wiśniewski, D Wohlfarth, I Yushmanov, and A Zhilin
Subjects: Physics, Nuclear and High Energy Physics, FOS: Physical sciences, Collision, Out of plane, Azimuth, In plane, Flow (mathematics), Incident energy, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, Beam (structure), Reference frame
Abstract: The incident energy at which the azimuthal distributions in semi-central heavy ion collisions change from in-plane to out-of-plane enhancement, E_tran, is studied as a function of mass of emitted particles, their transverse momentum and centrality for Au+Au collisions. The analysis is performed in a reference frame rotated with the sidewards flow angle, Theta_flow, relative to the beam axis. A systematic decrease of E_tran as function of mass of the reaction products, their transverse momentum and collision centrality is evidenced. The predictions of a microscopic transport model (IQMD) are compared with the experimental results., 32 pages, Latex, 22 eps figures, accepted for publication in Nucl. Phys. A
Published: 2000

38. Sideward flow of K$^+$ mesons in Ru+Ru and Ni+Ni reactions near threshold

Author: P Crochet, N Herrmann, K Wiśniewski, Y Leifels, A Andronic, R Averbeck, A Devismes, C Finck, A Gobbi, O Hartmann, K.D Hildenbrand, P Koczon, T Kress, R Kutsche, W Reisdorf, D Schüll, J.P Alard, V Barret, Z Basrak, N Bastid, I Belyaev, A Bendarag, G Berek, R Čaplar, N Cindro, P Dupieux, M Dželalija, M Eskef, Z Fodor, Y Grishkin, B Hong, J Kecskemeti, Y.J Kim, M Kirejczyk, M Korolija, R Kotte, M Kowalczyk, A Lebedev, K.S Lee, V Manko, H Merlitz, S Mohren, D Moisa, W Neubert, A Nianine, D Pelte, M Petrovici, C Plettner, F Rami, B de Schauenburg, Z Seres, B Sikora, K.S Sim, V Simion, K Siwek-Wilczyńska, V Smolyankin, A Somov, M Stockmeier, G Stoicea, M Vasiliev, P Wagner, D Wohlfarth, J.T Yang, I Yushmanov, A Zhilin, 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, Meson, Proton, 010308 nuclear & particles physics, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, in-medium potential, Nuclear physics, Transverse plane, Near threshold, strangeness, Flow (mathematics), sideward flow, 0103 physical sciences, directed flow, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Nucleon, collective motion
Abstract: Experimental data on K+ meson and proton sideward flow measured with the FOPI detector at SIS/GSI in the reactions Ru+Ru at 1.69 AGeV and Ni+Ni at 1.93 AGeV are presented. The K+ sideward flow is found to be anti-correlated (correlated) with the one of protons at low (high) transverse momenta. When compared to the predictions of a transport model, the data favour the existence of an in-medium repulsive K+ nucleon potential., 16 pages Revtex, 3 ps-figures, submitted to Phys. Lett. B
Published: 2000

39. Isospin tracing: A probe of nonequilibrium in central heavy-Ion collisions

Author: J. Mösner, W. Reisdorf, Philippe Crochet, James Ritman, Vladislav Manko, K. D. Hildenbrand, Y. Leifels, D. Wohlfarth, Y. Grigorian, S. Mohren, N. Herrmann, I. Belyaev, J. T. Yang, M. Eskef, P. Wagner, A. Nianine, M. Korolija, Gabriel Stoicea, D. Moisa, A. Zhilin, C. Plettner, B. de Schauenburg, P. Koczon, B. Sikora, M. Kirejczyk, R. Kotte, A. Gobbi, D. Pelte, Z. Basrak, Y. Grishkin, V. Simion, Yongsun Kim, Anton Andronic, Nicole Bastid, A. Devismes, D. Schüll, M. Dželalija, M. R. Stockmeier, A. Genoux-Lubain, A. Somov, K. S. Lee, J. P. Alard, T. Kress, Kwang Souk Sim, H. Folger, Fouad Rami, L. Fraysse, N. Cindro, Mihai Petrovici, C. Pinkenburg, Ralf Peter Averbeck, R. Čaplar, R. Kutsche, Pascal Dupieux, H. Merlitz, I. E. Yushmanov, Z. Seres, K. Wiśniewski, M. Kowalczyk, Ch. Finck, Byung-Sik Hong, Alexandre Lebedev, W. Neubert, Zoltan Fodor, G. Berek, A. Bendarag, K. Siwek-Wilczyńska, Valerie Ramillien Barret, M. A. Vasiliev, and J. Kecskemeti
Subjects: Physics, Projectile, Nuclear Theory, General Physics and Astronomy, Non-equilibrium thermodynamics, FOS: Physical sciences, Observable, Nuclear physics, Cross section (physics), Isospin, Phase space, Nuclear Physics - Experiment, Atomic physics, Nuclear Experiment (nucl-ex), Nucleon, Nuclear Experiment, Mixing (physics)
Abstract: Four different combinations of $^{96}_{44}$Ru and $^{96}_{40}$Zr nuclei, both as projectile and target, were investigated at the same bombarding energy of 400$A$ MeV using a $4 \pi$ detector. The degree of isospin mixing between projectile and target nucleons is mapped across a large portion of the phase space using two different isospin-tracer observables, the number of measured protons and the ${\rm t}/^{3}{\rm He}$ yield ratio. The experimental results show that the global equilibrium is not reached even in the most central collisions. Quantitative measures of stopping and mixing are extracted from the data. They are found to exhibit a quite strong sensitivity to the in-medium (n,n) cross section used in microscopic transport calculations., Comment: 4 pages RevTeX, 3 figures (ps files), submitted to Phys. Rev. Lett
Published: 1999

40. Flow angle from intermediate mass fragment measurements

Author: F. Rami, P. Crochet, R. Donà, B. de Schauenburg, P. Wagner, J.P. Alard, A. Andronic, Z. Basrak, N. Bastid, I. Belyaev, A. Bendarag, G. Berek, D. Best, R. Čaplar, A. Devismes, P. Dupieux, M. Dželalija, M. Eskef, Z. Fodor, A. Gobbi, Y. Grishkin, N. Herrmann, K.D. Hildenbrand, B. Hong, J. Kecskemeti, M. Kirejczyk, M. Korolija, R. Kotte, A. Lebedev, Y. Leifels, H. Merlitz, S. Mohren, D. Moisa, W. Neubert, D. Pelte, M. Petrovici, C. Pinkenburg, C. Plettner, W. Reisdorf, D. Schüll, Z. Seres, B. Sikora, V. Simion, K. Siwek-Wilczyńska, G. Stoicea, M. Stockmeir, M. Vasiliev, K. Wisniewski, D. Wohlfarth, I. Yushmanov, A. Zhilin, 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: Excitation function, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, FOS: Physical sciences, nuclear reactions, measured light, intermediate charged fragments, rapidity distributions, flow angle, expanding thermal source, hydrodynamical scaling, 01 natural sciences, Charged particle, Flow (mathematics), 0103 physical sciences, Saturation (graph theory), [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Impact parameter, Atomic physics, 010306 general physics, Anisotropy, Nuclear Experiment, Scaling, Energy (signal processing)
Abstract: Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 AMeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anisotropic expanding thermal source, we show that the value at saturation can provide a good estimate of the flow angle, $\Theta_{flow}$, in the participant region. It is found that $\Theta_{flow}$ depends strongly on the impact parameter. The excitation function of $\Theta_{flow}$ reveals striking deviations from the ideal hydrodynamical scaling. The data exhibit a steep rise of $\Theta_{\flow}$ to a maximum at around 250-400 AMeV, followed by a moderate decrease as the bombarding energy increases further., Comment: 28 pages Revtex, 6 figures (ps files), to appear in Nucl.Phys.A
Published: 1999

41. Heavy Ion Physics at Low, Intermediate and Relativistic Energies Using 4π Detectors

Author: J. Randrup, M. Petrovici, H. Stocker, A. Sandulescu, and D. Pelte
Subjects: International research, Nuclear physics, Physics, Detector, Heavy ion
Published: 1997
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42. Heavy Ion Physics at Low, Intermediate and Relativistic Energies using 4π Detectors

Author: H. Stocker, A. Sandulescu, D. Pelte, J. Randrup, and M. Petrovici
Subjects: Nuclear physics, International research, Physics, Detector, Heavy ion, Atomic physics
Published: 1997
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43. The role of the quantum dispersion in the Coulomb correction of Bose-Einstein correlations

Author: H. Merlitz and D. Pelte
Subjects: Physics, Nuclear and High Energy Physics, Nuclear Theory, Wave packet, FOS: Physical sciences, Bose–Einstein correlations, Schrödinger equation, Nuclear Theory (nucl-th), Momentum, symbols.namesake, Pion, Correlation function, Quantum mechanics, Coulomb, symbols, Quantum
Abstract: The time dependent Schroedinger equation for two identical and charged pions is solved using wavepacket states. It is shown that the expected Coulomb distortion in the momentum correlation function is obliterated by the dispersion of the localized states, and therefore becomes unobservable., 10 pages, LaTeX, 2 figures, 0.2 Mb postscript, submitted to Phys. Lett. B
Published: 1997

44. 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

45. 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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46. 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

47. 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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48. 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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49. Bose-Einstein Correlations of Pion Wavepackets

Author: D. Pelte and H. Merlitz
Subjects: Physics, Nuclear and High Energy Physics, Nuclear Theory, Wave packet, FOS: Physical sciences, Position and momentum space, Radius, Momentum, Nuclear Theory (nucl-th), Pion, Correlation function, Quantum mechanics, Phase space, Wave function
Abstract: A wavepacket model for a system of free pions, which takes into account the full permutation symmetry of the wavefunction and which is suitable for any phase space parametrization is developed. The properties of the resulting mixed ensembles and the two-particle correlation function are discussed. A physical interpretation of the chaoticity lambda as localizat of the pions in the source is presented. Two techniques to generate test-particles, which satisfy the probability densities of the wavepacket state, are studied: 1. A Monte Carlo procedure in momentum space based on the standard Metropolis technique. 2. A molecular dynamic procedure using Bohm's quantum theory of motion. In order to reduce the numerical complexity, the separation of the wavefunction into momentum space clusters is discussed. In this context th influence of an unauthorized factorization of the state, i. e. the omissio of interference terms, is investigated. It is shown that the correlation radius remains almost uneffected, but the chaoticity parameter decreases substantially. A similar effect is observed in systems with high multiplic where the omission of higher order corrections in the analysis of two-part correlations causes a reduction of the chaoticity and the radius. The approximative treatment of the Coulomb interaction between pions and source is investigated. The results suggest that Coulomb effects on the co radii are not symmetric for pion pairs of different charges. For negative the radius, integrated over the whole momentum spectrum, increases substan while for positive pions the radius remains almost unchanged., Comment: 15 pages, 8 figures, 0.8 Mb, uses ljour2-macro, Submitted to Z. Phys. A (1997)
Published: 1997
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50. 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

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