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1. Fragmentation studies with the CHIMERA detector at LNS in Catania: recent progress

Author

H. Wu, L. Auditore, J. Blicharska, M. Papa, G. Vannini, M. Trimarchi, S. M. Li, L. Zetta, Z. Majka, Angelo Pagano, S. Lo Nigro, M. L. Sperduto, T. Paduszynski, G. Lanzalone, G. Lanzanó, A. Chbihi, I. Skwira, M. Iacono-Manno, E. La Guidara, M.F Rivet, M. Bruno, J.P. Wieleczko, K. Siwek-Wilczyńska, Maria Colonna, R. Bougault, G.R. Sechi, E. Rosato, Monica Alderighi, Amalia Pop, V. Simion, J. Cibor, N. Le Neindre, J.C. Steckmeyer, F. Rizzo, F. Porto, E. De Filippo, L. Swiderski, P. Russotto, A. Anzalone, V. Baran, Zhigang Xiao, M. Bartolucci, R. Planeta, M. D'Agostino, J. Wilczynski, M. Di Toro, A. Bonasera, P. Guazzoni, A. Grzeszczuk, R. Dayras, S. Cavallaro, I. Berceanu, S. Russo, E. Geraci, F. Giustolisi, B. Borderie, J. Brzychczyk, M. Sassi, S. Kowalski, W. Gawlikowicz, E. Piasecki, A. Trifiro, Mariano Vigilante, G. Politi, L. Arena, S. Pirrone, W. Zipper, D. Guinet, G. Cardella, G. Manfredi, F. Amorini, C. Maiolino, M. Petrovici, M. B. Chatterjee, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), A. Pagano, M. Alderighi, F. Amorini, A. Anzalone, L. Arena, L. Auditore, V. Baran, M. Bartolucci, I. Berceanu, J. Blicharska, J.Brzychczyk, A. Bonasera, B. Borderie, R. Bougault, M. Bruno, G.Cardella, S. Cavallaro, M.B. Chatterjee, A. Chbihi, J. Cibor, M.Colonna, M. D'Agostino, R. Dayra, E. De Filippo, M. Di Toro, W.Gawlikowicz, E. Geraci, F. Giustolisi, A. Grzeszczuk, P. Guazzoni, D.Guinet, M. Iacono-Manno, S. Kowalski, E. La Guidara, G. Lanzano', G.Lanzalone, N.Le Neindre, S. Li, S. Lo Nigro, C. Maiolino, Z. Majka, G. Manfredi, T. Paduszynski, M. Papa, M. Petrovici, E. Piasecki, S.Pirrone, R. Planeta, G. Politi, A. Pop, F. Porto, M.F. Rivet, E. Rosato, F. Rizzo, S. Russo, P. Russotto, M. Sassi, G. Sechi, V. Simion, K. Siwek-Wilczynska, I. Skwira, M.L. Sperduto, J.C. Steckmeyer, L. Swiderski, A. Trifiro`, M. Trimarchi, G. Vannini, M. Vigilante, J.P. Wieleczko, J. Wilczynski, H. Wu, Z. Xiao, L. Zetta, W. Zipper, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Nuclear reaction, Nuclear and High Energy Physics, APPARATO DI RIVELAZIONE, TECNICHE DI IDENTIFICAZIONE, REAZIONI NUCLEARI SEMI-PERIFERICHE, PRODUZIONE DI FRAMMENTI DI MASSA INTERMEDIA, TEMPI DI PRODUZIONE DEI FRAMMENTI, Cyclotron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Particle identification, law.invention, Ion, Nuclear physics, law, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Detector, Charged particle, Time of flight, Nucleon
Abstract

The new detector CHIMERA, in its final 4π configuration, has been installed at Laboratori Nazionali del Sud (LNS) in Catania in January 2003. Beams of different energies ranging from protons to Au ions were delivered by the Tandem and the Super Conducting Cyclotron for nuclear reaction studies, in agreement with the approval of the Scientific Advisory Committee of LNS. Recent experimental results confirm very low energy thresholds of the trigger (below 0.5 MeV/nucleon), ensured within a wide dynamical range. Good characteristics of identification of light charged particles and heavy fragments have been obtained by using three detection techniques: Δ E-E , Δ E -time of flight, and the Pulse-Shape discrimination method. We present results of recent analysis concerning the production of intermediate mass fragments (IMF) in semi-peripheral collisions. Our results combined with theoretical Boltzmann-Nordheim-Vlasov simulations clearly demonstrate the presence of very fast processes of IMF production in the overlapping region of the target and projectile nuclei during re-separation, i.e. in the time scale comparable with the collision time. Evidence for slower, sequential-like production of IMF's is also shown.

Published
2004

2. Time sequence and time scale of intermediate mass fragment emission

Author

E. La Guidara, A. Chbihi, G. Vannini, M. Bruno, R. Bougault, M. Trimarchi, G. Cardella, M. L. Sperduto, I. Berceanu, S. Pirrone, M.F. Rivet, K. Schmidt, J.D. Frankland, M. B. Chatterjee, J.P. Wieleczko, B. Borderie, G. Lanzano, W. Zipper, N. Le Neindre, P. Guazzoni, L. Swiderski, E. Galichet, F. Rizzo, A. Trifirò, E. Geraci, Aldo Bonasera, S. Cavallaro, E. Piasecki, D. Guinet, C. Maiolino, S. M. Li, R. Dayras, F. Giustolisi, S. Russo, J. Blicharska, J. Cibor, Mihai Petrovici, F. Amorini, M. Papa, S. Kowalski, Maria Colonna, W. Gawlikowicz, M. D'Agostino, F. Porto, M. Sassi, P. Russotto, J. Wilczynski, Lucrezia Auditore, R. Planeta, G. Politi, Angelo Pagano, A. Grzeszczuk, Mariano Vigilante, Amalia Pop, G. Lanzalone, M. Di Toro, Zhigang Xiao, V. Baran, A. Anzalone, H. Wu, K. Siwek-Wilczyńska, E. De Filippo, I. Skwira, M. Iacono-Manno, E. Rosato, L. Zetta, Z. Majka, J. Brzychczyk, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), E., DE FILLIPPO, A., Pagano, J., Wilczynski, F., Amorini, A., Anzalone, N., Arena, L., Auditore, V., Baran, I., Berceanu, J., Blicharska, J., Brzychczyk, A., Bonasera, B., Borderie, R., Bougault, M., Bruno, G., Cardella, S., Cavallaro, M. B. CHATTERJEE A., Chbihi, J., Cibor, M., Colonna, M., D'Agostino, R., Dayra, M., DI TORO, J. D., Frankland, E., Galichet, W., Gawlikowicz, E., Geraci, F., Giustolisi, A., Grzeszczuk, P., Guazzoni, D., Guinet, M., IACONO MANNO, S., Kowalski, E., LA GUIDARA, G., Lanzan, G., Lanzalone, N., LE NEINDRE, S., Li, C., Maiolino, Z., Majka, M., Papa, M., Petrovici, E., Piasecki, S., Pirrone, R., Planeta, G., Politi, A., Pop, F., Porto, M. F., Rivet, F., Rizzo, Rosato, Elio, S., Russo, P., Russotto, M., Sassi, G., Schmidt, K., SIWEK WILCZYNSKA, I., Skwira, M. L., Sperduto, L., Swiderski, A., Trifir, M., Trimarchi, G., Vannini, Vigilante, Mariano, J. P., Wieleczko, H., Wu, Z., Xiao, L., Zetta, W., Zipper, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), E. De Filippo, A. Pagano, J. Wilczy´nski, F. Amorini, A. Anzalone, L. Auditore, V. Baran, I. Berceanu, J. Blicharska, J. Brzychczyk, A. Bonasera, B. Borderie, R. Bougault, M. Bruno, G. Cardella, S. Cavallaro, M. B. Chatterjee, A. Chbihi, J. Cibor, M. Colonna, M. D Agostino, R. Dayra, M. Di Toro, J. Frankland, E. Galichet, W. Gawlikowicz, E. Geraci, F. Giustolisi, A. Grzeszczuk, P. Guazzoni, D. Guinet, M. Iacono-Manno, S. Kowalski, E. La Guidara, G. Lanzano', G. Lanzalone, N. Le Neindre, S. Li, C. Maiolino, Z. Majka, M. Papa, M. Petrovici, E. Piasecki, S. Pirrone, R. PBaneta, G. Politi, A. Pop, F. Porto, M. F. Rivet, E. Rosato, F. Rizzo, S. Russo, P. Russotto, M. Sassi, K. Schmidt, K. Siwek-Wilczy´nska, I. Skwira, M. L. Sperduto, A. ´ Swiderski, A. Trifiro', M. Trimarchi, G. Vannini, M. Vigilante, J. P. Wieleczko, H. Wu, Z. Xiao, L. Zetta, and W. Zipper.

Subjects
Physics, Nuclear and High Energy Physics, Reaction mechanism, 010308 nuclear & particles physics, Relative velocity, Time sequence, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, 25.70.Mn, 25.70.Pq, Fragmentation (mass spectrometry), 0103 physical sciences, Heavy ion, Ion emission, Atomic physics, 010306 general physics, Nucleon, Ternary operation
Abstract

Matière Nucléaire NIM; Semiperipheral collisions in the $^{124}$Sn+${64}Ni reaction at 35 MeV/nucleon were studied using the forward part of the Charged Heavy Ion Mass and Energy Resolving Array. Nearly completely determined ternary events involving projectilelike fragments (PLF), targetlike fragments (TLF), and intermediate mass fragments (IMF) were selected. A new method of studying the reaction mechanism, focusing on the analysis of the correlations between relative velocities in the IMF+PLF and IMF+TLF subsystems, is proposed. The relative velocity correlations provide information on the time sequence and time scale of the neck fragmentation processes leading to production of IMFs. It is shown that the majority of light IMFs are produced within 40–80 fm/c after the system starts to reseparate. Heavy IMFs are formed at times of about 120 fm/c or later and can be viewed as resulting from two-step (sequential) neck rupture processes.

Published
2005

3. Gross Properties and Isotopic Phenomena in Spectator Fragmentation

Author

B. Czech, I. Iori, E. Le Gentil, C. Volant, Y. Leifels, Håkan T Johansson, A. S. Botvina, W. F. J. Müller, J. Łukasik, J.-E. Ducret, C. Sfienti, E. Rapisarda, J.D. Frankland, Margareta Hellström, H. Sann, W. Trautmann, K. Kezzar, U. Lynen, C.O. Bacri, R. Bassini, H. Weick, Cornelius Schwarz, J. Lühning, W. G. Lynch, H. Orth, Z. Majka, H. Simon, D. Henzlova, M. S. Wallace, P. Adrich, K. Sümmerer, M. Mocko, J. Brzychczyk, A. Chbihi, S. Bianchin, A. Le Fèvre, H. Emling, Thomas Aumann, G. Imme, T. Barczyk, A. Mykulyak, B. Zwieglinski, Piotr Pawłowski, A. Boudard, C. Boiano, J. Wiechula, J. Cibor, A.N. Otte, M. De Napoli, R. Palit, G. Raciti, A. Lafriakh, Alberto Pullia, A. Wieloch, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Istituto Nazionale di Fisica Nucleare, Sezione di Catania (INFN), Università degli studi di Catania [Catania], Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Istituto Nazionale di Fisica Nucleare (INFN), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Bertulani C.A., Gomes P.R.S., HusseinM.S., Szanto de ToledoA., ALADIN, Università degli studi di Catania = University of Catania (Unict), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, Projectile, media_common.quotation_subject, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Nuclear physics, Fragmentation (mass spectrometry), Criticality, 0103 physical sciences, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, 010306 general physics, ComputingMilieux_MISCELLANEOUS, media_common
Abstract

A systematic study of isotopic effects in the break-up of projectile spectators at relativistic energies has been performed with the ALADiN spectrometer at the GSI laboratory. Searching for signals of criticality in the fragment production we have applied the model independent universal fluctuations theory already proposed to track criticality signals in multifragmentation to our data. The fluctuation of the largest fragment charge and of the asymmetry of the two and three largest fragments and their bimodal distribution have also been analysed., Comment: 6 pages, 4 figures, IX International Conference on Nucleus-Nucleus Collisions, Rio de Janeiro, Brazil, August 28 - September 1, 2006

Published
2007

4. Quark–gluon plasma and color glass condensate at RHIC? The perspective from the BRAHMS experiment

Author

Bjørn Hallvard Samset, C. E. Jørgensen, J. Cibor, Calin Besliu, M. Mikelsen, F. Jundt, C. Chasman, Stephen Sanders, K. Hagel, I. S. Zgura, Anders Holm, D. R. Beavis, Catalin-Lucian Ristea, R. A. Scheetz, Oana Ristea, Borge Svane Nielsen, M. Germinario, Gunnar Løvhøiden, J. I. Jørdre, E. Enger, A. Makeev, Z. Majka, Ian Gardner Bearden, Trine Spedstad Tveter, P. Staszel, F. Videbæk, Y.K. Lee, R. Wada, A. K. Holme, Dieter Røhrich, Zhongbao Yin, B. Neumann, J. J. Gaardhøje, E. Jakobsen, Jongmin Lee, Michael Murray, B. Budick, Al. Jipa, D. Sandberg, S. Lindahl, R. R. Debbe, H. Ito, Peter Christiansen, I. Arsene, Christian Holm Christensen, E. J. Kim, Tomasz Kozik, R. Płaneta, Ole Hansen, R. Karabowicz, Fouad Rami, H. Bøggild, D. Ouerdane, J. B. Natowitz, T. M. Larsen, 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 BRAHMS

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, High Energy Physics::Phenomenology, Hadron, FOS: Physical sciences, Plasma, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Color-glass condensate, Nuclear physics, Quark–gluon plasma, Energy density, Bibliography, High Energy Physics::Experiment, Heavy ion, Nuclear Experiment (nucl-ex), Nuclear Experiment, Jet quenching
Abstract

We review the main results obtained by the BRAHMS collaboration on the properties of hot and dense hadronic and partonic matter produced in ultrarelativistic heavy ion collisions at RHIC. A particular focus of this paper is to discuss to what extent the results collected so far by BRAHMS, and by the other three experiments at RHIC, can be taken as evidence for the formation of a state of deconfined partonic matter, the so called quark-gluon-plasma (QGP). We also discuss evidence for a possible precursor state to the QGP, i.e. the proposed Color Glass Condensate., 32 pages, 18 figures

Published
2005

5. RECENT RESULTS FROM THE BRAHMS EXPERIMENT AT RHIC

Author

Z. Yin, Z. Majka, B. Neuman, C. Ristea, Stephen Sanders, Borge Svane Nielsen, Gunnar Løvhøiden, J. I. Jørdre, Y. K. Lee, Christian Holm Christensen, H. Bøggild, P. Staszel, D. Ouerdane, I. Arsene, J. B. Natowitz, Calin Besliu, K. Hagel, Tomasz Kozik, H. Ito, Svein Lindal, Alexandru Jipa, D. Sandberg, B. Budick, M. Mikelsen, F. Jundt, Peter Christiansen, Ian Gardner Bearden, Dieter Røhrich, Trine Spedstad Tveter, Jongmin Lee, T. M. Larsen, R. R. Debbe, R. Lystad, R. Pł Aneta, I. S. Zgura, R. Karabowicz, Fouad Rami, Michael D. Murray, F. Videbæk, E. J. Kim, E. Enger, D. R. Beavis, A. Makeev, J. J. Gaardhøje, Oana Ristea, R. A. Sheetz, R. Wada, J. Cibor, C. Chasman, M. Germinario, Bjørn Hallvard Samset, C. E. Jørgensen, 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), Berndt Müller, Chung-I Tan, and BRAHMS

Subjects
Physics, Nuclear and High Energy Physics, High Energy Density Matter, Astronomy and Astrophysics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Atomic and Molecular Physics, and Optics, Charged particle, 25.75.-q, 25.75.Dw, Color-glass condensate, Nuclear physics, Reaction dynamics, Quark–gluon plasma, Particle, Rapidity, Nuclear Experiment, Relativistic Heavy Ion Collider
Abstract

We present the results obtained by the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC) for three colliding systems, namely: Au + Au , d + Au and p + p at [Formula: see text]. The main focus here is to give an overview of the main results on the reaction dynamics and on the properties of hot and high energy density matter produced in utra-relativistic heavy ion collisions. Measurement of particle production, particle spectra over a large rapidity interval as well as high pt measurements related to nuclear modification in Au + Au and d + Au collision are discussed. The observed number of charged particles produced per unit of rapidity at the central rapidity region indicates that a high energy density (> 5 GeV/fm3) system is created at the initial stage of the Au + Au reaction. From the particle spectra we deduced significant radial expansion (β ≈ 0.75) which is consistent with the large initial energy density. For Au + Au at η = 0 we observe the suppression of the high p T particles as compared to the elementary collisions, whereas for the d + Au reaction the Cronin type enhancement is observed. We also discuss to what extent these results can be taken as evidence for the quark gluon plasma (QGP). Finally, we present the nuclear modification effects in d + Au reaction as a function of rapidity and consider whether the observed suppression at forward rapidities constitutes sufficient evidence for a possible precursor state to the QGP, i.e. the Color Glass Condensate (CGC).

Published
2005

6. Forward and midrapidity like-particle ratios from p+p collisions at s=200 GeV

Author

J. I. Jørdre, P. Staszel, Michael Murray, Ian Gardner Bearden, Stephen Sanders, H. Bøggild, D. Ouerdane, Dieter Røhrich, A. Wieloch, C. Chasman, K. Hagel, Gunnar Løvhøiden, M. Mikelsen, J. Cibor, F. Jundt, Y. K. Lee, D. Sandberg, M. Germinario, E. Jakobsen, Jongmin Lee, J. B. Natowitz, R. R. Debbe, Bjørn Hallvard Samset, K. Olchanski, D Rohrich, C. E. Jørgensen, A. K. Holme, Christian Holm Christensen, E. J. Kim, D. R. Beavis, Alexandru Jipa, F. Videbæk, E. Enger, Z. Majka, J. Norris, R. Płaneta, JI Jordre, Peter Christiansen, R. A. Scheetz, I. S. Zgura, H. Ito, Anders Holm, R. Karabowicz, Fouad Rami, J. J. Gaardhøje, B. Budick, T. Keutgen, A. Makeev, T. M. Larsen, Tomasz Kozik, Calin Besliu, R. Wada, Z. Yin, Trine Spedstad Tveter, C. Ristea, and Borge Svane Nielsen

Subjects
Baryon, Physics, Nuclear and High Energy Physics, Transverse momentum, Theoretical models, Rapidity, Baryon number, Atomic physics, Rest frame, Beam energy
Abstract

We present a measurement of π − / π + , K − / K + and p ¯ / p from p + p collisions at s = 200 GeV over the rapidity range 0 y 3.4 . For p T 2.0 GeV / c we see no significant transverse momentum dependence of the ratios. All three ratios are independent of rapidity for y ≲ 1.5 and then steadily decline from y ∼ 1.5 to y ∼ 3 . The π − / π + ratio is below unity for y > 2.0 . The p ¯ / p ratio is very similar for p + p and 20% central Au + Au collisions at all rapidities. In the fragmentation region the three ratios seem to be independent of beam energy when viewed from the rest frame of one of the protons. Theoretical models based on quark–diquark breaking mechanisms overestimate the p ¯ / p ratio up to y ≲ 3 . Including additional mechanisms for baryon number transport such as baryon junctions leads to a better description of the data.

Published
2005

7. Rapidity dependent strangeness measurements in BRAHMS experiment at RHIC

Author

J H Lee, (for the BRAHMIS Collaboration), I G Bearden, D Beavis, C Besliu, B Budick, H Bøggild, C Chasman, C H Christensen, P Christiansen, J Cibor, R Debbe, E Enger, J J Gaardhøje, M Germinario, K Hagel, O Hansen, A Holm, H Ito, E Jakobsen, A Jipa, F Jundt, J I Jørdre, C E Jørgensen, R Karabowicz, E J Kim, T Kozik, T M Larsen, Y K Lee, G Løvhøiden, Z Majka, A Makeev, M Mikelsen, M Murray, J Natowitz, B S Nielsen, J Norris, K Olchanski, J Olness, D Ouerdane, R P aneta, F Rami, C Ristea, D Röhrich, B H Samset, D Sandberg, S J Sanders, P Staszel, T S Tveter, F Videbæk, R Wada, A Wieloch, Z Yin, and I S Zgura

Subjects
Physics, Nuclear physics, Nuclear reaction, Nuclear and High Energy Physics, Particle physics, Pion, Meson, Hadron, Transverse mass, Rapidity, Strangeness, Nuclear Experiment, Charged particle
Abstract

Particle production of charged kaons in central Au+Au collisions at has been studied as a function of rapidity by the BRAHMS collaboration at RHIC. The kaon spectral shapes are described well by an exponential in transverse mass for the rapidity range of 0 ≤ yK ≤ 3.3 with smoothly decreasing inverse slopes as the rapidity increases. For the charged kaon to pion ratios, while there is no significant rapidity dependence for the K+/π+ ratio, the K−/π− ratio shows a significant decrease from y ≈ 1 towards higher rapidities. The systematics of K−/K+ and ratios in the measured rapidity range demonstrates a strongly correlated behaviour which can be described by thermal–statistical models.

Published
2003

8. The BRAHMS experiment at RHIC

Author

F. Jundt, L. Dutka, L Antvorskov, M Kajetanowicz, Borge Svane Nielsen, E. Jakobsen, Jongmin Lee, Zbigniew Sosin, M Adamczyk, J. Westergaard, T. Keutgen, A. Makeev, D. R. Beavis, K Ashktorab, Christian Holm Christensen, E.K. Olsen, B. Budick, P. Staszel, R. Planeta, R. A. Scheetz, F. Videbæk, Michael Murray, Z. Majka, Tomasz Kozik, K. Hagel, J. Hammond, Gunnar Løvhøiden, Dieter Røhrich, K. Grotowski, T. M. Larsen, Bjørn Hallvard Samset, Y. Blyakhman, J. Brzychczyk, H. Bøggild, E. Baker, Al. Jipa, D. Ouerdane, J. B. Natowitz, R. Wada, H. Ito, R. Debbe, A. K. Holme, C. E. Jørgensen, E. J. Kim, J Sørensen, E Kotula, Calin Besliu, N. Lindegaard, Peter Christiansen, I. S. Zgura, K. Olchanski, C. Pearson, O.B. Rasmussen, Anders Holm, J. J. Gaardhøje, J. Cibor, A. Wieloch, Trine Spedstad Tveter, K Pena, K. Asselta, Ole Hansen, Y. K. Lee, C. Chasman, J Engelhardt, D. Phillips, E McBreen, J. I. Jørdre, H Diaz, M Justice, Ian Gardner Bearden, J.W. Olness, Fouad Rami, J.C. Hansen, T.F. Thorsteinsen, and Stephen Sanders

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Spectrometer, Physics::Instrumentation and Detectors, Tracking (particle physics), Particle identification, Nuclear physics, Momentum, Quark–gluon plasma, High Energy Physics::Experiment, Rapidity, Nuclear Experiment, Instrumentation, Event (particle physics), Cherenkov radiation
Abstract

The BRAHMS experiment at RHIC was conceived to pursue the understanding of nuclear matter under extreme conditions by detailed measurements of charged hadrons over the widest possible range of rapidity and transverse momentum. The experiment consists of two spectrometers with complementary charged hadron detection capabilities as well as a series of global detectors for event characterization. A series of tracking detectors, time-of-flight arms and Cherenkov detectors enables momentum determination and particle identification over a wide range of rapidity and transverse momentum. Technical details and performance results are presented for the various detector subsystems. The performance of the entire system working together is shown to meet the goals of the experiment.

Published
2003

9. Results from the BRAHMS experiment at RHIC

Author

D R$ouml$hrich for the BRAHMS Collaboration, I G Bearden, D Beavis, C Besliu, Y Blyakhman, J Brzychczyk, B Budick, H B$oslash$ggild, C Chasman, C H Christensen, P Christiansen, J Cibor, R Debbe, J J Gaardh$oslash$je, M Germinario, K Grotowski, K Hagel, O Hansen, A Holm, A K Holme, H Ito, E Jakobsen, A Jipa, J I Jordre, F Jundt, C E J$oslash$rgensen, T Keutgen, E J Kim, T Kozik, T M Larsen, J H Lee, Y K Lee, G L$oslash$vh$oslash$iden, Z Majka, A Makeev, B McBreen, M Murray, J Natowitz, B S Nielsen, K Olchanski, J Olness, D Ouerdane, R P$lslash$aneta, F Rami, D R$ouml$hrich, B Samset, D Sandberg, S Sanders, R A Sheetz, Z Sosin, P Staszel, T F Thorsteinsen, T S Tveter, F Videb$aelig$k, R Wada, A Wieloch, and I S Zgura

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Antiproton, Pseudorapidity, Rapidity, Multiplicity (chemistry), Relativistic Heavy Ion Collider, Charged particle, Late summer
Abstract

Results from the BRAHMS Collaboration for the inaugural physics run with the relativistic heavy ion collider (RHIC), Au + Au collisions at √sNN = 130 GeV in the late summer of 2000, and some results of the very first data from the summer of 2001 at √sNN = 200 GeV are presented. Here the main focus is on the determination of the pseudorapidity distribution of charged particles as a function of collision centrality and on the measurement of the antiproton to proton and the K− to K+ ratios as a function of rapidity. The pseudorapidity density at midrapidity reaches dN(ch)/dη = 553 ± 36 for the most central collisions (0–5%) at √sNN = 130 GeV; the corresponding number for a higher energy is dN(ch)/dη = 632 ± 36, demonstrating an increase in multiplicity of about 14%. The measured antiproton/proton ratios peak at midrapidity around N()/N(p) = 0.64 ± 0.06 and drop to 0.41 ± 0.04 at y ≈ 2 for √sNN = 130 GeV reactions; the K− to K+ ratios are 0.90 ± 0.06 (y ≈ 0) and 0.83 ± 0.1 (y ≈ 2.5).

Published
2002

10. Charged particle densities from Au+Au collisions at =130 GeV

Author

I.G Bearden, D Beavis, C Besliu, Y Blyakhman, J Brzychczyk, B Budick, H Bøggild, C Chasman, C.H Christensen, P Christiansen, J Cibor, R Debbe, J.J Gaardhøje, K Grotowski, K Hagel, O Hansen, A Holm, A.K Holme, H Ito, E Jakobsen, A Jipa, J.I Jørdre, F Jundt, C.E Jørgensen, T Keutgen, E.J Kim, T Kozik, T.M Larsen, J.H Lee, Y.K Lee, G Løvhøiden, Z Majka, A Makeev, E McBreen, M Murray, J Natowitz, B.S Nielsen, K Olchanski, J Olness, D Ouerdane, R Płaneta, F Rami, D Röhrich, B.H Samset, S.J Sanders, R.A Sheetz, Z Sosin, P Staszel, T.F Thorsteinsen, T.S Tveter, F Videbæk, R Wada, A Wieloch, and I.S Zgura

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Range (particle radiation), Pseudorapidity, Particle, High Energy Physics::Experiment, Rapidity, Multiplicity (mathematics), Nuclear Experiment, Nucleon, Scaling, Charged particle
Abstract

We present charged particle densities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at sqrt{s_{NN}}=130 GeV. An integral charged particle multiplicity of 3860+/-300 is found for the 5% most central events within the pseudorapidity range -4.7

Published
2001

11. Entrance channel dynamics in 40Ca+40Ca at 35A MeV

Author

R. Wada, J. Cibor, K. Hagel, N. Marie, J. Li, W. Q. Shen, Akira Ono, J. B. Natowitz, Y. Zhao, Cyclotron institute, and Cyclotron Institute

Subjects
25.70Pq, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Wave packet, Nuclear Theory, Dynamics (mechanics), Motion (geometry), Centroid, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Entrance channel, Classical mechanics, Diffusion process, 0103 physical sciences, 010306 general physics
Abstract

International audience; The entrance channel dynamics of the 40Ca+40Ca reaction at 35A MeV is modeled with the recently developed QMD codes, EQMD and AMD-V. Drastic differences are observed in the entrance channel dynamics calculated by the two models. AMD-V with a Gogny force reproduces the experimental results over all. The importance of the introduction of the diffusion process to the centroid motion of wave packets is suggested.

Published
1998

12. Isoscaling in central $^{124]$Sn + $^{64}$Ni, $^{112}$Sn + $^{58}$Ni collisions at 35 A MeV

Author

A. Chbihi, J.C. Steckmeyer, M. Iacono-Manno, A. Italiano, J. Brzychczyk, S. Kowalski, E. La Guidara, V. Baran, E. Piasecki, M. Papa, G. Vannini, L. Zetta, F. Giustolisi, D. Guinet, Z. Majka, S. Lo Nigro, R. Barnà, J. Cibor, M. Trimarchi, M.F. Rivet, Maria Colonna, S. M. Li, Antonio Trifiro, Amalia Pop, Mariano Vigilante, M. Di Toro, C. Maiolino, G. Lanzanó, P. Guazzoni, R. Bougault, M. Petrovici, D. De Pasquale, F. Porto, Angelo Pagano, S. Cavallaro, A. Bonasera, M. Bartolucci, A. Grzeszczuk, S. Russo, L. Auditore, G. Cardella, S. Pirrone, W. Zipper, N. Le Neindre, M. L. Sperduto, E. Geraci, Bernard Borderie, G. Lanzalone, G. Manfredi, M. D'Agostino, P. Russotto, M. Alderighi, Zhigang Xiao, H. Wu, A. Anzalone, G. Politi, J.P. Wieleczko, M. Bruno, I. Berceanu, G.R. Sechi, V. Simion, Elio Rosato, E. De Filippo, J. Wilczynski, J. Blicharska, T. Paduszynski, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), E. GERACI, M. ALDERIGHI, A. ANZALONE, L. AUDITORE, V. BARAN, R. BARNA', M. BARTOLUCCI, I. BERCEANU, J. BLICHARSKA, A. BONASERA, B. BORDERIE, R. BOUGAULT, BRUNO M., J. BRZYCHCZYK, G. CARDELLA, S. CAVALLARO, A. CHBIHI, J. CIBOR, M. COLONNA, M. D'AGOSTINO, E .DE FILIPPO, D. DE PASQUALE, M. DI TORO, F. GIUSTOLISI, A. GRZESZCZUK, P. GUAZZONI, D. GUINET, M. IACONO-MANNO, A. ITALIANO, S. KOWALSKI, E. LA GUIDARA, G. LANZALONE, G. LANZANO', N. LE NEINDRE, S. LI, S. LO NIGRO, C. MAIOLINO, Z. MAJKA, G. MANFREDI, T. PADUSZYNSKI, A. PAGANO, M. PAPA, M. PETROVICI, E. PIASECKI, S. PIRRONE, G. POLITI, A. POP, F. PORTO, M. F. RIVET, E. ROSATO, S. RUSSO, P. RUSSOTTO, G. SECHI, V. SIMION, M. L. SPERDUTO, J. C. STECKMEYER, A. TRIFIRO, M. TRIMARCHI, G. VANNINI, M. VIGILANTE, J. P. WIELECZKO, J. WILCZYNSKI, H. WU, Z. XIAO, L. ZETTA, W. ZIPPER, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Phase transition, Heavy ion–nucleus reactions, Nuclear isospin, Nuclear fragmentation, MATERIA NUCLEARE, Nuclear Theory, Hadron, 112Sn(58Ni, FRAMMENTAZIONE NUCLEARE, ISOSPIN, REAZIONI NUCLEARI FRA IONI PESANTI, ISOTOPI, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, 25.70.-z, 25.70.Pq, 24.10.Pa, 02.50.Sk, 124Sn(64Ni, Isotopes, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Nuclear matter, X), Physics, 010308 nuclear & particles physics, Baryon, Isospin, E=35 A MeV, Nuclear reactions, Atomic physics, Nucleon
Abstract

124 Sn+ 64 Ni and 112 Sn+ 58 Ni reactions at 35 A MeV incident energy were studied by using the 688 Si–CsI telescopes of the forward part (1°⩽ θ lab ⩽30°) of CHIMERA multi-detector. The most central part, 1% of the total measured cross section was selected by means of a multidimensional analysis of the experimental observables. The detected isotopes of light fragments (3⩽ Z ⩽8) provided information on breakup temperatures of the emitting sources. The space–time structure of these sources was deduced from fragment correlations. An odd–even effect in the fragment production, enhanced by the isospin of the entrance channel, was observed. Freeze-out unbound neutron-to-proton relative densities for both studied reactions have been deduced, indicating for a possible isospin distillation mechanism related to a phenomenon of the liquid–gas phase transition in asymmetric systems.

Published
2004

13. The dependence of fission time-scales on fragment mass asymmetry in the 20Ne+165Ho reaction at 50A MeV

Author

J. Li, J. B. Natowitz, Z. Majka, K. Hagel, R. Wada, Y. Lou, D. Utley, N. Mdeiwayeh, R. Tezkratt, B. Xiao, and J. Cibor

Subjects
Physics, Nuclear and High Energy Physics, Fission, Nuclear Theory, Monte Carlo method, Multiplicity (mathematics), Alpha particle, Spectral line, Coincidence, Condensed Matter::Soft Condensed Matter, Excited state, Atomic physics, Nuclear Experiment, Excitation
Abstract

The pre-scission and post-scission multiplicities of alpha particles were determined in coincidence with fission fragments for four windows of exit channel mass asymmetry in the reaction 20Ne+165Ho at 50A MeV. The technique used employed a kinematic analysis of the energy spectra of alpha particles as a function of the emission angle with respect to the fission axis. Using a procedure of fitting the experimental energy spectra with those resulting from a Monte Carlo simulation program, the total multiplicity of alpha particles was separated into pre-scission and post-scission components. Using the pre-scission and post-scission multiplicities, neutron multiplicity measurements and other empirical observations, both the initial excitation energy and the excitation energy at scission of the compound nucleus were determined. The pre-scission times in the de-excitation of a highly excited 178W compound nucleus with initial excition energy of 570 MeV were evaluated using statistical model calculations. Only a small decrease in scission time was derived for the most asymmetric events studied. The possible contribution of very damped deep inelastic processes is discussed.

Published
1997

14. Quantum statistical thermodynamics of hot finite nuclear systems: Temperatures and isotopic yield ratios

Author

J. Cibor, P. Staszel, K. Hagel, J. Li, J. B. Natowitz, N. Mdeiwayeh, Y. Zhao, R. Wada, and Z. Majka

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Isotope, Yield (chemistry), Nuclear Theory, Thermodynamics, Yield ratio, Nuclear Experiment, Nuclear system, Nuclear matter, Quantum statistical mechanics, Quantum
Abstract

We investigate the importance of the quantum statistics and deexcitation of primary fragments on the isotope yield ratio temperature determination. A phenomenological formula is presented which allows derivation of the temperature of the decaying nuclear system at the freeze-out time from the measured double yield ratios of two isotope pairs. This prescription is applied to the recent ALADIN and EOS Collaboration data. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

15. Study of the violent collisions between63Cu+232Th at 35 MeV/nucleon

Author

J. Cibor, K. Hagel, R. Wada, Z. Majka, Tomasz Kozik, Zbigniew Sosin, B. Xiao, L. Lou, R. Tezkratt, D. Utley, P. Staszel, J. Li, and J. B. Natowitz

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Fission, Projectile, Neutron, Atomic physics, Multiplicity (chemistry), Nuclear Experiment, Nucleon, Nuclear matter, Charged particle, Excitation
Abstract

A study of the decay of hot and heavy composite nuclei produced in the violent collisions between {sup 63}Cu and {sup 232}Th at 35A MeV is presented. The measurement of fission fragment correlations indicates that {approximately} 70{percent} of the projectile linear momentum can be transferred to the fissioning system. Heavy reaction products were observed at a laboratory angle of {theta}=6{degree} in coincidence with neutrons, light charged particles, and intermediate mass fragments. The dynamical aspects of the collisions between the projectile and target nuclei were investigated using the computer code CHIMERA which is based upon the molecular dynamics concept. Asymptotic characteristics of the reaction products were confronted with results of calculations of the tandem CHIMERA plus GEMINI codes. The data and model comparisons show that a composite system of mass as high as 275 amu and with an excitation energy {approximately} 1 GeV is formed in the most violent collisions. Some of the heavy reaction remnants are located on the fragment mass versus velocity plane inside the area where the evaporation residues resulting from the decay of the hot composite system are expected. A high neutron multiplicity associated with these events indicates their origin in the most dissipative events. However, amore » low cross section for the production of these remnants and the close similarity of their characteristics to the fission fragments do not allow more conclusive statements. {copyright} {ital 1997} {ital The American Physical Society}« less

Published
1997

16. Excitation energies and temperatures of hot nuclei produced in the reactions of63Cu+197Au at35AMeV

Author

Ferid Haddad, J. Li, Tomasz Kozik, J. Cibor, K. Hagel, J. B. Natowitz, Shalom Shlomo, B. Xiao, A. Kolomiets, R. Wada, Zbigniew Sosin, Z. Majka, D. Utley, Y. Lou, R. Tezkratt, N. Mdeiwayeh, and M. Shimooka

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, Isotope, Fission, Isotopes of lithium, Population, Multiplicity (mathematics), Excited state, Atomic physics, Nuclear Experiment, education, Isotopes of helium, Excitation
Abstract

Observations of heavy remnants emitted at forward angles with high velocities and high associated particle multiplicities have been used to select central collisions of 35A MeV {sup 63}Cu with {sup 197}Au. The data indicate that these remnants, both fission fragments and evaporation residuelike products, result from the deexcitation of nuclei with A{approximately}225{endash}240 having excitation energies of {approximately} 800{endash}1300 MeV. Similar particle multiplicities are observed for both evaporative and fission decay channels. Modeling the results with hybrid codes which treat entrance channel dynamics followed by sequential statistical decay requires the inclusion of some delay in the fission channel to produce heavy remnants with mass A{ge}130, but the trend of the predicted velocities of these heavy remnants is different from that of the experiments. Calculations with a dynamic model based on the molecular dynamics approach have also been performed and lead to similar results. He and Li isotope yield ratios and the apparent temperatures derived from those ratios are similar to those previously reported for excited nuclei in this mass region. Temperatures derived from other yield ratios are also similar once a self-consistent treatment, taking into account population and decay of known excited states, is applied. The derived temperatures show little variation more » with excitation energy, suggesting that a limiting temperature may be reached at relatively low excitation energy, although the interpretation of this result and the determination of the actual initial value of this temperature is model dependent. Comments on the application of the double isotope yield ratio technique to extraction of the nuclear caloric curve are made. {copyright} {ital 1997} {ital The American Physical Society} « less

Published
1997

17. Isotope correlations as a probe for freeze-out charaterization: central $^{124}$Sn+$^{64}$Ni, $^{112}$Sn+$^{58}$Ni collisions

Author

S. Pirrone, M. L. Sperduto, Bernard Borderie, Monica Alderighi, M. Di Toro, J. Brzychczyk, P. Russotto, L. Zetta, Z. Majka, S. Lo Nigro, F. Porto, S. Kowalski, Maria Colonna, M. Bartolucci, A. Anzalone, Angelo Pagano, M. Papa, G. Vannini, S. Russo, Amalia Pop, S. Cavallaro, J. Wilczynski, G.R. Sechi, V. Simion, T. Paduszynski, A. Chbihi, D. Guinet, J. Blicharska, J.C. Steckmeyer, E. Piasecki, M. Bruno, G. Cardella, M.F. Rivet, M. Iacono-Manno, Elio Rosato, E. De Filippo, G. Lanzalone, F. Giustolisi, Marina Trimarchi, G. Manfredi, Antonio Trifiro, E. Geraci, P. Guazzoni, Zhigang Xiao, H. Wu, I. Berceanu, Mariano Vigilante, A. Grzeszczuk, G. Lanzanó, R. Bougault, V. Baran, S. M. Li, E. La Guidara, M. Petrovici, J. Cibor, A. Bonasera, W. Zipper, N. Le Neindre, J.P. Wieleczko, C. Maiolino, M. D'Agostino, Lucrezia Auditore, G. Politi, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), E. GERACI, M. ALDERIGHI, A. ANZALONE, L. AUDITORE, V. BARAN, M. BARTOLUCCI, I. BERCEANU, J. BLICHARSKA, A. BONASERA, B. BORDERIE, R. BOUGAULT, BRUNO M., J. BRZYCHCZYK, G. CARDELLA, S. CAVALLARO, A. CHBIHI, J. CIBOR, M. COLONNA, M. D'AGOSTINO, E .DE FILIPPO, M. DI TORO, F. GIUSTOLISI, A. GRZESZCZUK, P. GUAZZONI, D. GUINET, M. IACONO-MANNO, S. KOWALSKI, E. LA GUIDARA, G. LANZALONE, G. LANZANO', N. LE NEINDRE, S. LI, S. LO NIGRO, C. MAIOLINO, Z. MAJKA, G. MANFREDI, T. PADUSZYNSKI, A. PAGANO, M. PAPA, M. PETROVICI, E. PIASECKI, S. PIRRONE, G. POLITI, A. POP, F. PORTO, M. F. RIVET, E. ROSATO, S. RUSSO, P. RUSSOTTO, G. SECHI, V. SIMION, M. L. SPERDUTO, J. C. STECKMEYER, A. TRIFIRO, M. TRIMARCHI, G. VANNINI, M. VIGILANTE, J. P. WIELECZKO, J. WILCZYNSKI, H. WU, Z. XIAO, L. ZETTA, W. ZIPPER, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, RAPPORTO FRA DENSITA’ FRA NEUTRONI E PROTONI, Nuclear and High Energy Physics, TEMPERATURA E VOLUME DELLA SORGENTE, Proton, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, SORGENTE ECCITATA, 0103 physical sciences, Incident energy, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, DIMENSIONE, Physics, Isotope, 010308 nuclear & particles physics, REAZIONI NUCLEARI CENTRALI, RESE DI ISOTOPI, Characterization (materials science), Volume (thermodynamics), Yield (chemistry), Atomic physics
Abstract

124Sn+64Ni and 112Sn+58Ni reactions at 35 AMeV incident energy were studied with the forward part of CHIMERA multi-detector. The most central collisions were selected by means of a multidimensional analysis. The characteristics of the source formed in the central collisions, as size, temperature and volume, were inspected. The measured isotopes of light fragments (3, 4 pages, Contribution to 8th International Conference on Nucleus-Nucleus Collisions, Moscow 2003

Published
2003

18. Results from the BRAHMS experiment at RHIC

Author

J. I. Jørdre, Bjørn Hallvard Samset, J. Norris, M. Mikkelsen, R. A. Sheetz, Y. Blyakhman, Stephen Sanders, K. Grotowski, Ole Hansen, A. K. Holme, D. Sandberg, K. Hagel, C. E. Jørgensen, T. M. Larsen, I. S. Zgura, K. Olchanski, F. Videbæk, P. Staszel, B. McBreen, J. J. Gaardhøje, R. Karabowicz, Fouad Rami, Trine Spedstad Tveter, Dieter Røhrich, R. Planeta, R. R. Debbe, Alexandru Jipa, Dieter Roehrich, J. B. Natowitz, Ian Gardner Bearden, T. Keutgen, Tomasz Kozik, C. Chasman, A. Makeev, Gunnar Løvhøiden, H. Ito, E. Enger, Michael D. Murray, Y. K. Lee, F. Jundt, B. Budick, M. Germinario, J. Cibor, Christian Holm Christensen, E. J. Kim, H. Bøggild, D. Ouerdane, J. Brzychczyk, Peter Christiansen, Borge Svane Nielsen, Calin Besliu, Z. Majka, R. Wada, Z. Yin, A. Wieloch, D. R. Beavis, E. Jakobsen, Jongmin Lee, and Zbigniew Sosin

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, Nuclear Theory, Hadron, Elementary particle, Atomic and Molecular Physics, and Optics, Charged particle, Nuclear physics, Baryon, Pion, Pseudorapidity, High Energy Physics::Experiment, Rapidity, Nuclear Experiment
Abstract

Results from the BRAHMS collaboration for Au+Au collisions at √ S NN = 200 GeV are presented, focussing on the measurement of the net-proton rapidity distribution, the determination of the pseudorapidity distribution of charged particles and on the rapidity distributions of pions and kaons.

Published
2003

19. Neutron recognition in the LAND detector for large neutron multiplicity

Author

E. Rapisarda, E. Le Gentil, C. Volant, T. Barczyk, A. Mykulyak, I. Iori, Håkan T Johansson, K. Sümmerer, A.N. Otte, M. De Napoli, P. Adrich, R. Bassini, J. Brzychczyk, Z. Majka, J. Łukasik, C. Sfienti, H. Weick, Giuseppe Verde, J.D. Frankland, S. Kupny, H. Sann, D. M. Rossi, A. Wieloch, M. D. Salsac, Cornelius Schwarz, S. Leray, M. Veselsky, A. Chbihi, D. Henzlova, Piotr Pawłowski, Y. Leifels, W. Trautmann, A. Boudard, S. Bianchin, A. Lafriakh, Alberto Pullia, H. Emling, J. Immè, J. Wiechula, C. Boiano, C.O. Bacri, J.-E. Ducret, U. Lynen, J. Lühning, S. Hlavac, M. Mocko, W. G. Lynch, H. Orth, H. Simon, A. Le Fèvre, Thomas Aumann, G. Raciti, T. Gorbinet, M. S. Wallace, K. Boretzky, M. B. Tsang, K. Kezzar, Stefano Panebianco, Margareta Hellström, J. Cibor, B. Zwieglinski, B. Czech, R. Palit, W. F. J. Müller, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Nuclear and High Energy Physics, LAND, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], neutron detection, 01 natural sciences, Particle detector, Nuclear physics, 0103 physical sciences, Neutron detection, Heavy-ion reactions, Neutron, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], heavy-ion reactions, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Instrumentation, Physics, 010308 nuclear & particles physics, Detector, Measuring instrument, Nucleon
Abstract

The performance of the LAND neutron detector is studied. Using an event-mixing technique based on one-neutron data obtained in the S107 experiment at the GSI laboratory, we test the efficiency of various analytic tools used to determine the multiplicity and kinematic properties of detected neutrons. A new algorithm developed recently for recognizing neutron showers from spectator decays in the ALADIN experiment S254 is described in detail. Its performance is assessed in comparison with other methods. The properties of the observed neutron events are used to estimate the detection efficiency of LAND in this experiment., 16 pages, 8 figures

Published
2012

20. Erratum: Isospin-dependent multifragmentation of relativistic projectiles [Phys. Rev. C 83, 024608 (2011)]

Author

J. Lühning, W. G. Lynch, H. Orth, H. Simon, I. Iori, E. Le Gentil, A. S. Botvina, J. Lukasik, Giuseppe Verde, G. Imme, Håkan T Johansson, C. Volant, H. Emling, A. Wieloch, Cornelius Schwarz, C. Boiano, Y. Leifels, H. Sann, A. Chbihi, H. Weick, Wolfgang Müller, T. Barczyk, A. Mykulyak, C. Sfienti, M. S. Wallace, S. Bianchin, K. Sümmerer, J.-E. Ducret, E. Rapisarda, J.D. Frankland, C.O. Bacri, J. Brzychczyk, A. Lafriakh, Alberto Pullia, Piotr Pawłowski, P. Adrich, Riza Ogul, J. Cibor, B. Zwieglinski, R. Bassini, A. Le Fèvre, M. B. Tsang, Thomas Aumann, R. Palit, U. Lynen, G. Raciti, Z. Majka, B. Czech, I. N. Mishustin, Nihal Büyükçizmeci, U. Atav, Margareta Hellström, W. Trautmann, M. Mocko, D. Henzlova, A. Boudard, J. Wiechula, A.N. Otte, M. De Napoli, K. Kezzar, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, 25.70.Pq, 25.70.Mn, 21.65.Ef, 99.10.Cd, 010308 nuclear & particles physics, Projectile, Isospin, 0103 physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, 01 natural sciences
Published
2012

21. Isospin-dependent multifragmentation of relativistic projectiles

Author

R. Bassini, Giuseppe Verde, K. Sümmerer, E. Le Gentil, J. Lühning, A. Boudard, Håkan T Johansson, H. Emling, W. G. Lynch, H. Orth, J. Wiechula, D. Henzlova, C. Volant, J. Łukasik, H. Simon, I. Iori, B. Zwieglinski, P. Adrich, H. Weick, A. Lafriakh, Alberto Pullia, C. Boiano, Z. Majka, Y. Leifels, A.N. Otte, M. De Napoli, Piotr Pawłowski, Margareta Hellström, Cornelius Schwarz, B. Czech, C. Sfienti, Wolfgang Müller, T. Barczyk, A. Mykulyak, Nihal Büyükçizmeci, A. S. Botvina, J.D. Frankland, S. Bianchin, K. Kezzar, M. B. Tsang, U. Atav, J.-E. Ducret, A. Wieloch, E. Rapisarda, G. Raciti, Igor Mishustin, J. Cibor, R. Palit, A. Chbihi, M. S. Wallace, J. Brzychczyk, U. Lynen, G. Imme, M. Mocko, W. Trautmann, H. Sann, C.O. Bacri, Riza Ogul, A. Le Fèvre, Thomas Aumann, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, 010308 nuclear & particles physics, Hadron, FOS: Physical sciences, Fermion, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 3. Good health, Nuclear Theory (nucl-th), Baryon, Nuclear physics, Isospin, Excited state, 0103 physical sciences, Neutron, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Dimensionless quantity
Abstract

The N/Z dependence of projectile fragmentation at relativistic energies has been studied with the ALADIN forward spectrometer at the GSI Schwerionen Synchrotron (SIS). Stable and radioactive Sn and La beams with an incident energy of 600 MeV per nucleon have been used in order to explore a wide range of isotopic compositions. For the interpretation of the data, calculations with the statistical multifragmentation model for a properly chosen ensemble of excited sources were performed. The parameters of the ensemble, representing the variety of excited spectator nuclei expected in a participant-spectator scenario, are determined empirically by searching for an optimum reproduction of the measured fragment-charge distributions and correlations. An overall very good agreement is obtained. The possible modification of the liquid-drop parameters of the fragment description in the hot freeze-out environment is studied, and a significant reduction of the symmetry-term coefficient is found necessary to reproduce the mean neutron-to-proton ratios /Z and the isoscaling parameters of Z, 23 pages, 29 figures, published in Physical Review C

Published
2011

22. Discriminant Analysis and Secondary-Beam Charge Recognition

Author

I. Iori, S. Bianchin, Z. Majka, Håkan T Johansson, H. Weick, M. B. Tsang, E. Le Gentil, P. Adrich, C. Volant, J. Łukasik, M. S. Wallace, T. Barczyk, Cornelius Schwarz, J.-E. Ducret, A. Mykulyak, Y. Leifels, E. Rapisarda, A. Lafriakh, Margareta Hellström, Alberto Pullia, B. Czech, A. Le Fèvre, H. Sann, Thomas Aumann, G. Imme, C. Sfienti, J.D. Frankland, W. F. J. Müller, C.O. Bacri, Giuseppe Verde, J. Cibor, H. Emling, U. Lynen, R. Palit, A. Chbihi, C. Boiano, J. Lühning, M. Mocko, G. Raciti, K. Sümmerer, K. Kezzar, W. G. Lynch, H. Orth, J. Brzychczyk, H. Simon, A. S. Botvina, B. Zwieglinski, W. Trautmann, Piotr Pawłowski, A. Wieloch, D. Henzlova, A. Boudard, J. Wiechula, A.N. Otte, M. De Napoli, R. Bassini, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Istituto Nazionale di Fisica Nucleare (INFN), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Istituto Nazionale di Fisica Nucleare, Sezione di Catania (INFN), Università degli studi di Catania [Catania], ALADIN, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Università degli studi di Catania = University of Catania (Unict)

Subjects
Nuclear and High Energy Physics, Statistical methods, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Fragmentation (mass spectrometry), 0103 physical sciences, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Instrumentation, Physics, Isotope, radioactive beams, 02.50.Sk, 25.70.Mn, 010308 nuclear & particles physics, Projectile, Detector, projectile fragmentation, Linear discriminant analysis, discriminant analysis, Isospin, Beam (structure)
Abstract

The discriminant-analysis method has been applied to optimize the exotic-beam charge recognition in a projectile fragmentation experiment. The experiment was carried out at the GSI using the fragment separator (FRS) to produce and select the relativistic secondary beams, and the ALADIN setup to measure their fragmentation products following collisions with Sn target nuclei. The beams of neutron poor isotopes around 124La and 107Sn were selected to study the isospin dependence of the limiting temperature of heavy nuclei by comparing with results for stable 124Sn projectiles. A dedicated detector to measure the projectile charge upstream of the reaction target was not used, and alternative methods had to be developed. The presented method, based on the multivariate discriminant analysis, allowed to increase the efficacy of charge recognition up to about 90%, which was about 20% more than achieved with the simple scalar methods., Comment: 6 pages, 7 eps figures, elsart, submitted to Nucl. Instr. and Meth. A

Published
2008

23. Properties of the initial participant matter interaction zone in near-Fermi-energy heavy-ion collisions

Author

G. Nebbia, A. Ruangma, S. Pesente, G. Prete, Giuseppe Viesti, L. Qin, Sherry Yennello, G. A. Souliotis, R. Wada, Z. Majka, D. Fabris, J. B. Natowitz, T. Materna, Y. El Masri, M. Cinausero, Arturo Alejandro Menchaca-Rocha, Chen Zhen, Akira Ono, E. Martin, Sandra Moretto, V. Rizzi, S. Kowalski, A.L. Keksis, Ruben Alfaro, T. Keutgen, Yu-Gang Ma, K. Hagel, Arnulfo Martínez-Dávalos, Marcello Lunardon, D. V. Shetty, P. Staszel, M. Veselsky, Jian-Song Wang, J. Cibor, E. M. Winchester, Michael D. Murray, W. Zipper, and UCL - SC/PHYS - Département de physique

Subjects
Coalescence (physics), Physics, Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, Fermi energy, Charged particle, Heavy ion, Neutron, Nuclear Experiment (nucl-ex), Atomic physics, Impact parameter, Multiplicity (chemistry), Nuclear Experiment, Nucleon
Abstract

The sizes, temperatures and free neutron to proton ratios of the initial interaction zones produced in the collisions of 40 MeV/nucleon $^{40}$Ar + $^{112}$Sn and 55 MeV/nucleon$^{27}$Al + $^{124}$Sn are derived using total detected neutron plus charged particle multiplicity as a measure of the impact parameter range and number of participant nucleons. The size of the initial interaction zone, determined from a coalescence model analysis, increases significantly with decreasing impact parameter. The temperatures and free neutron to proton ratios in the interaction zones are relatively similar for different impact parameter ranges and evolve in a similar fashion., 7 pages, 8 figures

Published
2007

24. N/Z Dependence of Projectile Fragmentation

Author

W. G. Lynch, H. Orth, H. Simon, I. Iori, E. Le Gentil, J. Lukasik, Giuseppe Verde, G. Imme, Håkan T Johansson, C. Volant, H. Emling, A. Wieloch, Cornelius Schwarz, C. Boiano, K. Suemmerer, Y. Leifels, H. Sann, A. Chbihi, H. Weick, T. Barczyk, A. Mykulyak, C. Sfienti, M. S. Wallace, S. Bianchin, J.-E. Ducret, E. Rapisarda, J.D. Frankland, C.O. Bacri, J. Brzychczyk, A. Lafriakh, Alberto Pullia, Piotr Pawłowski, P. Adrich, J. Cibor, M. Hellstroem, B. Zwieglinski, R. Bassini, A. Le Fèvre, M. B. Tsang, Thomas Aumann, R. Palit, U. Lynen, G. Raciti, Z. Majka, B. Czech, W. F. Mueller, W. Trautmann, M. Mocko, D. Henzlova, A. Boudard, J. Wiechula, A.N. Otte, M. De Napoli, J. Luehning, K. Kezzar, A. S. Botvina, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALADIN, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Spectrometer, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, FOS: Physical sciences, Limiting, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, Neutron detection, Atomic number, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Projectile fragmentation, Beam (structure)
Abstract

The N/Z dependence of projectile fragmentation at relativistic energies has been studied in a recent experiment at the GSI laboratory with the ALADiN forward spectrometer coupled to the LAND neutron detector. Besides a primary beam of 124Sn, also secondary beams of 124La and 107Sn delivered by the FRS fragment separator have been used in order to extend the range of isotopic compositions of the produced spectator sources. With the achieved mass resolution of \Delta A/A \approx 1.5%, lighter isotopes with atomic numbers Z \le 10 are individually resolved. The presently ongoing analyses of the measured isotope yields focus on isoscaling and its relation to the properties of hot fragments at freeze-out and on the derivation of chemical freeze-out temperatures which are found to be independent of the isotopic composition of the studied systems. The latter result is at variance with the predictions for limiting temperatures as obtained with finite-temperature Hartree-Fock calculations., Comment: 11 pages, 5 figures, Proceedings of International Workshop on Nuclear Dynamics in Heavy-Ion Reactions and Neutron Stars, Beijing, July 10-14, 2007, to appear in International Journal of Modern Physics E

Published
2007
Full Text
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25. Centrality dependent particle production aty=0andy~1in Au+Au collisions atsNN=200 GeV

Author

Trine Spedstad Tveter, Stephen Sanders, B. Budick, K. Hagel, Bjørn Hallvard Samset, C. E. Jørgensen, Calin Besliu, C. Chasman, H. Ito, J. Cibor, Jongmin Lee, Ian Gardner Bearden, A. Makeev, D. R. Beavis, Gunnar Løvhøiden, Z. Majka, Y. K. Lee, P. Staszel, Tomasz Kozik, Borge Svane Nielsen, B. Neumann, Alexandru Jipa, R. R. Debbe, D. Sandberg, M. Germinario, Peter Christiansen, T. M. Larsen, R. Karabowicz, Fouad Rami, R. Wada, J. I. Jørdre, Christian Holm Christensen, E. J. Kim, F. Videbæk, Z. Yin, C. Ristea, R. A. Scheetz, I. Arsene, I. S. Zgura, Oana Ristea, R. Płaneta, M. Mikelsen, F. Jundt, J. J. Gaardhøje, E. Enger, Dieter Røhrich, H. Bøggild, D. Ouerdane, J. B. Natowitz, Michael D. Murray, Svein Lindal, and R. Lystad

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Elementary particle, 01 natural sciences, 7. Clean energy, Baryon, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Nucleon, Centrality
Abstract

Particle production of identified charged hadrons, ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}},{K}^{\ifmmode\pm\else\textpm\fi{}},p$, and $\overline{p}$ in Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=$ 200 GeV, has been studied as a function of transverse momentum and collision centrality at $y=0$ and $y~1$ by the BRAHMS experiment at Brookhaven National Laboratory's Relativistic Heavy-Ion Collider. Significant collective transverse flow at kinetic freeze-out has been observed in the collisions. The magnitude of the flow rises with the collision centrality. Proton and kaon yields relative to the pion production increase strongly as the transverse momentum increases and also increase with centrality. Particle yields per participant nucleon show a weak dependence on the centrality for all particle species. Hadron production remains relatively constant within one unit around midrapidity in Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=$ 200 GeV.

Published
2005

26. Towards the critical behavior for the light nuclei by NIMROD detector

Author

V. Rizzi, Z. Majka, E. Fioretto, D. Fabris, G. Nebbia, G. Prete, G. A. Souliotis, Sherry Yennello, Michael Murray, E. M. Winchester, Giuseppe Viesti, M. Cinausero, Arnulfo Martínez-Dávalos, N. Marie, A. Makeev, A.L. Keksis, P. Smith, J. B. Natowitz, R. Wada, D. V. Shetty, M. Veselsky, P. Staszel, L. Qin, Y. El Masri, Marcello Lunardon, Ruben Alfaro, K. Hagel, A. Ruangma, Yu-Gang Ma, J. Cibor, Jian-Song Wang, Arturo Alejandro Menchaca-Rocha, E. Martin, Th. Keutgen, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), D. Adamova, A. Kugler, P. Tlusty, and Normandie Université (NU)-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, Light nucleus, Phase transition, Nuclear Theory, 010308 nuclear & particles physics, Detector, FOS: Physical sciences, Observable, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, Critical point (thermodynamics), 0103 physical sciences, Nimrod, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Nuclear theory, Excitation
Abstract

The critical behavior for the light nuclei with A$\sim 36$ has been investigated experimentally by the NIMROD multi-detectors. The wide variety of observables indicate the critical point has been reached in the disassembly of hot nuclei at an excitation energy of 5.6$\pm$0.5 MeV/u., 4 pages, 2 figures; Proceeding of 18th Nuclear Physics Division Conference of the Euro. Phys. Society (NPDC18) "Phase transitions in strongly interacting matter", Prague, 23.8.-29.8. 2004. To be published in Nuclear Physics A

Published
2005

27. The New Physics at RHIC. From Transparency to High p$_t$ Suppression

Author

Ian Gardner Bearden, B. McBreen, Tomasz Kozik, Stephen Sanders, M. Germinario, Trine Spedstad Tveter, Ole Hansen, M. Mikelsen, Bjørn Hallvard Samset, I. S. Zgura, Calin Besliu, Y.K. Lee, F. Jundt, K. Hagel, R. A. Scheetz, P. Staszel, Anders Holm, C. E. Jørgensen, B. Budick, J. J. Gaardhøje, J. I. Jørdre, Christian Holm Christensen, Z. Majka, H. Bøggild, D. Ouerdane, J. B. Natowitz, H. Ito, Oana Ristea, Michael D. Murray, Z. Yin, R. Płaneta, Svein Lindal, T. M. Larsen, C. Ristea, R. Lystad, Borge Svane Nielsen, D. Sandberg, R. R. Debbe, C. Chasman, J. Norris, Alexandru Jipa, D. R. Beavis, R. Wada, J. Cibor, Jongmin Lee, E. Enger, R. Karabowicz, A. Makeev, D. Ro¨hrich, E. J. Kim, Fouad Rami, Gunnar Løvhøiden, Peter Christiansen, I. Arsene, and B. Neumann

Subjects
Thermal equilibrium, Nuclear reaction, Physics, Nuclear and High Energy Physics, Hadron, FOS: Physical sciences, Parton, Charged particle, Nuclear physics, Color model, Strange matter, Quark–gluon plasma, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment
Abstract

Heavy ion collisions at RHIC energies (Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV) exhibit significant new features as compared to earlier experiments at lower energies. The reaction is characterized by a high degree of transparency of the collisions partners leading to the formation of a baryon-poor central region. In this zone, particle production occurs mainly from the stretching of the color field. The initial energy density is well above the one considered necessary for the formation of the Quark Gluon Plasma, QGP. The production of charged particles of various masses is consistent with chemical and thermal equilibrium. Recently, a suppression of the high transverse momentum component of hadron spectra has been observed in central Au+Au collisions. This can be explained by the energy loss experienced by leading partons in a medium with a high density of unscreened color charges. In contrast, such high $p_t$ jets are not suppressed in d+Au collisions suggesting that the high $p_t$ suppression is not due to initial state effects in the ultrarelativistic colliding nuclei., 15 pages, 11 figures. to appear in Nucl. Physics A. Invited talk at 'Nucleus-Nucleus Collisions 2003' conference, Moscow

Published
2004

28. Mass and Isospin Effects in Multifragmentation

Author

E. Le Gentil, C. Volant, H. Weick, I. Iori, J. Lühning, W. G. Lynch, H. Orth, A. Lafriakh, J.-E. Ducret, E. Rapisarda, W. Trautmann, J. Cibor, H. Simon, D. Henzlova, Alberto Pullia, R. Palit, A. Le Fèvre, Thomas Aumann, Y. Leifels, M. B. Tsang, C. Boiano, G. Imme, W. F. J. Müller, Margareta Hellström, B. Czech, Giuseppe Verde, M. Mocko, A. S. Botvina, U. Lynen, Håkan T Johansson, K. Sümmerer, M. S. Wallace, H. Sann, A. Sokolov, J. Brzychczyk, J. Łukasik, C.O. Bacri, K. Kezzar, Cornelius Schwarz, A. Wieloch, H. Emling, T. Barczyk, A. Mykulyak, P. Adrich, C. Sfienti, J.D. Frankland, A. Chbihi, R. Bassini, Z. Majka, B. Zwieglinski, A.N. Otte, M. De Napoli, G. Raciti, A. Boudard, J. Wiechula, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Spectrometer, 010308 nuclear & particles physics, Projectile, Nuclear Theory, FOS: Physical sciences, Multiplicity (mathematics), Observable, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Breakup, 01 natural sciences, Nuclear physics, Isospin, 0103 physical sciences, Incident energy, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment
Abstract

A systematic study of isospin effects in the breakup of projectile spectators at relativistic energies has been performed with the ALADiN spectrometer at the GSI laboratory (Darmstadt). Four different projectiles 197Au, 124La, 124Sn and 107Sn, all with an incident energy of 600 AMeV, have been used, thus allowing a study of various combinations of masses and N/Z ratios in the entrance channel. The measurement of the momentum vector and of the charge of all projectile fragments with Z>1 entering the acceptance of the ALADiN magnet has been performed with the high efficiency and resolution achieved with the TP-MUSIC IV detector. The Rise and Fall behavior of the mean multiplicity of IMFs as a function of Zbound and its dependence on the isotopic composition has been determined for the studied systems. Other observables investigated so far include mean N/Z values of the emitted light fragments and neutron multiplicities. Qualitative agreement has been obtained between the observed gross properties and the predictions of the Statistical Multifragmentation Model., 10 pages,7 figure, 18th Nuclear Physics Division Conference of the EPS, Prague, submitted to Nucl. Phys. A

Published
2004
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29. Critical Behavior in Light Nuclear Systems: Experimental Aspects

Author

G. Nebbia, M. Cinausero, R. Wada, G. A. Souliotis, D.V. Shetty, A. Ruangma, Jian-Song Wang, A.L. Keksis, E. M. Winchester, Y. El Masri, Martin Veselsky, E Fioretto, V. Rizzi, Z. Majka, L. Qin, Michael Murray, J. Cibor, Ruben Alfaro, M. Lunardon, K. Hagel, Arnulfo Martínez-Dávalos, G. Viesti, P. Staszel, A. Makeev, Yu-Gang Ma, Th. Keutgen, Nathalie Marie, G. Prete, Sherry Yennello, Arturo Alejandro Menchaca-Rocha, E. Martin, P. Smith, D. Fabris, J. B. Natowitz, Cyclotron institute, Cyclotron Institute, UCL - SC/PHYS - Département de physique, and UCL - MD/ESP - Ecole de santé publique

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Phase transition, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, Kinetic energy, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), Semi-empirical mass formula, Critical point (thermodynamics), 0103 physical sciences, 25.70.Pq, 24.60.Ky, 05.70.Jk, Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Nuclear Experiment, Critical exponent
Abstract

An extensive experimental survey of the features of the disassembly of a small quasi-projectile system with $A \sim$ 36, produced in the reactions of 47 MeV/nucleon $^{40}$Ar + $^{27}$Al, $^{48}$Ti and $^{58}$Ni, has been carried out. Nuclei in the excitation energy range of 1-9 MeV/u have been investigated employing a new method to reconstruct the quasi-projectile source. At an excitation energy $\sim$ 5.6 MeV/nucleon many observables indicate the presence of maximal fluctuations in the de-excitation processes. The fragment topological structure shows that the rank sorted fragments obey Zipf's law at the point of largest fluctuations providing another indication of a liquid gas phase transition. The caloric curve for this system shows a monotonic increase of temperature with excitation energy and no apparent plateau. The temperature at the point of maximal fluctuations is $8.3 \pm 0.5$ MeV. Taking this temperature as the critical temperature and employing the caloric curve information we have extracted the critical exponents $\beta$, $\gamma$ and $\sigma$ from the data. Their values are also consistent with the values of the universality class of the liquid gas phase transition. Taken together, this body of evidence strongly suggests a phase change in an equilibrated mesoscopic system at, or extremely close to, the critical point., Comment: Physical Review C, in press; some discussions about the validity of excitation energy in peripheral collisions have been added; 24 pages and 32 figures; longer abstract in the preprint

Published
2004
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30. Mid-rapidity emission in 124Sn, 124Xe + 124Sn, 112Sn reactions at 28 MeV/nucleon

Author

M. Veselsky, N. Marie, R. Wada, E. Fioretto, G. Nebbia, Jian-Song Wang, G. Prete, Z. Majka, P. Smith, K. Hagel, G. A. Souliotis, Sherry Yennello, D. Fabris, M. Cinausero, Yu-Gang Ma, J. B. Natowitz, J. Cibor, Th. Keutgen, A. Makeev, D. V. Shetty, E. M. Winchester, P. Staszel, A.L. Keksis, Arturo Alejandro Menchaca-Rocha, E. Martin, V. Rizzi, Giuseppe Viesti, L. Qin, Ruben Alfaro, Marcello Lunardon, Michael D. Murray, A. Ruangma, Arnulfo Martínez-Dávalos, and Y. El Masri

Subjects
Nuclear physics, Physics, Nuclear reaction, Baryon, Nuclear and High Energy Physics, Stable isotope ratio, Helium-3, Neutron, Atomic physics, Nuclear Experiment, Nucleon, Isotopes of helium, Charged particle
Abstract

Light charged particle, (Z = 2), and intermediate-mass fragments, (2 124 Sn, 124 Xe + 124 Sn, 112 Sn reactions at 28 MeV/nucleon. With increasing centrality, the heavier 6 He isotope is found to be emitted closer to mid-rapidity than the lighter 3 He isotope. The emission becomes increasingly favorable for particles with higher charge, Z, indicating mid-rapidity region to be not only neutron rich, but also a rich source of heavy fragment (cluster) formation.

Published
2004

31. Evidence of critical behavior in the disassembly of nuclei with A$\sim$36

Author

E. Fioretto, D.V. Shetty, G. Prete, G. Nebbia, J. Cibor, Michael Murray, E. M. Winchester, M. Cinausero, M. Lunardon, Sherry Yennello, K. Hagel, Th. Keutgen, P. Smith, Arturo Alejandro Menchaca-Rocha, E. Martin, Martin Veselsky, Yu-Gang Ma, V. Rizzi, Ruben Alfaro, D. Fabris, A. Makeev, A.L. Keksis, G. A. Souliotis, N. Marie, P. Staszel, L. Qin, J. S. Wang, Z. Majka, Y. El Masri, G. Viesti, R. Wada, Arnulfo Martínez-Dávalos, A. Ruangma, J. B. Natowitz, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Light nucleus, 010308 nuclear & particles physics, Nuclear Theory, FOS: Physical sciences, Observable, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Flattening, Caloric curve, Critical point (thermodynamics), 0103 physical sciences, Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, 25.70.Pq, 05.70.Jk, 24.60.Ky, Excitation
Abstract

A wide variety of observables indicate that maximal fluctuations in the disassembly of hot nuclei with A ~ 36 occur at an excitation energy of 5.6 +- 0.5 MeV/u and temperature of 8.3 +- 0.5 MeV. Associated with this point of maximal fluctuations are a number of quantitative indicators of apparent critical behavior. The associated caloric curve does not appear to show a flattening such as that seen for heavier systems. This suggests that, in contrast to similar signals seen for liquid-gas transitions in heavier nuclei, the observed behavior in these very light nuclei is associated with a transition much closer to the critical point., Comment: v2: Major changes, new model calculations, new figures

Published
2004

32. Reaction dynamics and multifragmentation in Fermi energy heavy ion reactions

Author

Jian-Song Wang, R. Alfarro, A. Makeev, G. A. Souliotis, D. Fabris, L. Qin, J. Cibor, M. Cinausero, E. M. Winchester, Yu-Gang Ma, V. Rizzi, N. Marie, Giuseppe Viesti, A. Ruangma, Marcello Lunardon, P. Smith, W. Zipper, J. B. Natowitz, Arturo Alejandro Menchaca-Rocha, E. Martin, Arnulfo Martínez-Dávalos, G. Nebbia, G. Prete, E. Fioretto, S. Kowalski, K. Hagel, Michael D. Murray, P. Staszel, Sherry Yennello, R. Wada, M. Veselsky, Y. El Masri, D. V. Shetty, A.L. Keksis, T. Keutgen, Z. Majka, Akira Ono, UCL - SC/PHYS - Département de physique, UCL - MD/ESP - Ecole de santé publique, Cyclotron institute, Cyclotron Institute, and NIMROD

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Elliptic flow, 25.70.Pq, Nuclear Theory, FOS: Physical sciences, Fermi energy, Observable, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Spectral line, 3. Good health, Nuclear physics, Molecular dynamics, Reaction dynamics, 0103 physical sciences, Atomic physics, Multiplicity (chemistry), Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Nuclear Experiment
Abstract

The reaction systems, 64Zn + 58Ni, 64Zn + 92Mo, 64Zn + 197Au, at 26A, 35A and 47A MeV, have been studied both in experiments with a 4$\pi$ detector array, NIMROD, and with Antisymmetrized Molecular Dynamics model calculations employing effective interactions corresponding to soft and stiff equations of state (EOS). Direct experimental observables, such as multiplicity distributions, charge distributions, energy spectra and velocity spectra, have been compared in detail with those of the calculations and a reasonable agreement is obtained. The velocity distributions of $\alpha$ particles and fragments with Z >= 3 show distinct differences in calculations with the soft EOS and the stiff EOS. The velocity distributions of $\alpha$ particle and Intermediate Mass Fragments (IMF's) are best described by the stiff EOS. Neither of the above direct observables nor the strength of the elliptic flow are sensitive to changes in the in-medium nucleon-nucleon (NN) cross sections. A detailed analysis of the central collision events calculated with the stiff EOS revealed that multifragmentation with cold fragment emission is a common feature predicted for all reactions studied here. A possible multifragmentation scenario is presented; after the preequilibrium emission ceases in the composite system, cold light fragments are formed in a hotter gas of nucleons and stay cold until the composite system underdoes multifragmentation. For reaction with 197Au at 47A MeV a significant radial expansion takes place. For reactions with 58Ni and 92Mo at 47A MeV semi-transparency becomes prominent. The differing reaction dynamics drastically change the kinematic characteristics of emitted fragments. This scenario gives consistent explanations for many existing experimental results in the Fermi energy domain., Comment: 34 pages, 43 figures

Published
2004

33. Intermediate mass fragments and isospin dependence inSn124,Xe124+Sn124,Sn112reactions at28MeV∕nucleon

Author

D. V. Shetty, A. Keksis, E. Martin, A. Ruangma, G. A. Souliotis, M. Veselsky, E. M. Winchester, S. J. Yennello, K. Hagel, Y. G. Ma, A. Makeev, N. Marie, M. Murray, J. B. Natowitz, L. Qin, P. Smith, R. Wada, J. Wang, M. Cinausero, E. Fioretto, G. Prete, D. Fabris, M. Lunardon, G. Nebbia, V. Rizzi, G. Viesti, J. Cibor, Z. Majka, P. Staszel, R. Alfaro, A. Martinez-Davalos, A. Menchaca-Rocha, Y. El Masri, and T. Keutgen

Subjects
Physics, Nuclear and High Energy Physics, Proton, Isotope, 010308 nuclear & particles physics, Nuclear Theory, 01 natural sciences, Spectral line, Charged particle, Ion, Nuclear physics, 13. Climate action, Isospin, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Intermediate mass fragment (Z>2) emission in Sn-124,Xe-124+Sn-124,Sn-112 reactions at 28 MeV /nucleon were studied using neutron ion multidetector for reaction oriented dynamics, a 4pi charged particle detection system. A number of observables, such as isotopic yield distributions, energy spectra of light charged particles and intermediate mass fragments, isotopic and isobaric yield ratios, and average neutron to proton ratios are investigated. These observables show significant dependence on the isospin N/Z of the reacting system. It is observed that the formation of neutron-rich clusters are correlated with the excess neutrons in the composite system and depends on the temperature of the emitting source. The origin of light particles and fragments was studied through observations of rapidity distribution as a function of collision violence. With increasing centrality, the heavier He-6 isotope is found to be emitted closer to the midrapidity region than the lighter He-3 isotope. The emission of heavy fragments from the midrapidity region becomes increasingly favorable for fragments with higher charge Z . The results suggest that the midrapidity region is not only neutron rich but also a rich source of heavy fragment (cluster) formation.

Published
2003

34. Fragment excitation energies at freeze-out in84Kr+93Nbcollisions at 45 MeV/nucleon

Author

K. Hagel, J. Cibor, D. G. Sarantites, R. J. Charity, L. G. Sobotka, R. Wada, J.P. Wieleczko, E. Plagnol, E. Norbeck, J.L. Barreto, Gerard Auger, P. Staszel, R. Dayras, Z. Majka, J. B. Natowitz, Nathalie Marie, D. W. Stracener, and Yves Roland Schutz

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Fragment (computer graphics), Nuclear Theory, Charge (physics), Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Charged particle, Entrance channel, Nuclear physics, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Excitation
Abstract

The emission of light charged particles and intermediate-mass fragments (IMF’s) from central collisions of 45 MeV/nucleon 84Kr with 93Nb has been studied. Violent collisions have been selected using the total collected charge condition. The analysis of the primary IMF excitation energies has been performed for four bins of the detected IMF charge (2

Published
2001

35. Charged particle multiplicities at BRAHMS

Author

Borge Svane Nielsen, Stephen Sanders, Trine Spedstad Tveter, Y. K. Lee, Michael D. Murray, K. Grotowski, R. Wada, Ian Gardner Bearden, J.W. Olness, T. M. Larsen, J. Cibor, K. Hagel, Peter Christiansen, F. Videbæk, Z. Majka, D. R. Beavis, R. R. Debbe, E. J. Kim, I. S. Zgura, Anders Holm, E. Jakobsen, Jongmin Lee, Zbigniew Sosin, J. J. Gaardhøje, Calin Besliu, J. I. Jørdre, Alexandru Jipa, C. Chasman, R. A. Sheetz, R. Planeta, T.F. Thorsteinsen, Christian Holm Christensen, K. Olchanski, Bjørn Hallvard Samset, Gunnar Løvhøiden, Tomasz Kozik, T. Keutgen, Ole Hansen, A Wieloch, C. E. Jørgensen, A. Makeev, Fouad Rami, B. Budick, H. Bøggild, D. Ouerdane, J. B. Natowitz, H. Ito, F. Jundt, J. Brzychczyk, Y. Blyakhman, A. K. Holme, P. Staszel, B. McBreen, Dieter Røhrich, 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), BRAHMS, and Heyd, Yvette

Subjects
[PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nuclear physics, Physics, Nuclear and High Energy Physics, Pseudorapidity, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Hadron, Data analysis, General Physics and Astronomy, Nuclear Experiment, Collision, Charged particle, Characterization (materials science)
Abstract

Charged particle pseudorapidity densities are presented for the 197Au+197Au reaction at $$\sqrt {s_{NN} } = 130$$ . These densities provide an essential characterization of the underlying reactions mechanisms for ultra-relativistic heavy-ion collision. This talk details how the global charged particle yields are measured at BRAHMS and presents some preliminary results from the analysis of data taken during the first year of the RHIC experimental program.

Published
2001

36. Emission of Unstable Clusters from Hot Yb Compound Nuclei

Author

J. Cibor, E. Fioretto, G. Nebbia, G. Prete, R. Wada, Giuseppe Viesti, Y. El Masri, D. Fabris, L. G. Sobotka, M. Cinausero, K. Hagel, R. J. Charity, Michael D. Murray, Hu-Shan Xu, J. B. Natowitz, and Andreas Wagner

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Alpha particle, Atomic physics, Isotopes of beryllium, Isotopes of helium, Radioactive decay, Energy (signal processing), Charged particle, Spectral line
Abstract

Neutrons and isotopically resolved light charged particles have been detected in coincidence with evaporation residues produced in the reaction $E/A=11 \mathrm{MeV}$ ${}^{60}\mathrm{Ni}{+}^{100}\mathrm{Mo}.$ Multiplicities of evaporated particle-unstable clusters have been determined from correlations in the emission of these light particles. The decay of the short-lived ${}^{5}\mathrm{He}$ and ${}^{8}\mathrm{Be}$ ${(E}^{*}=3.04 \mathrm{MeV})$ states was found to be affected by the Coulomb field of the compound nucleus in accordance with theoretical estimates. The contributions to the measured kinetic-energy distributions of stable fragments from the sequential decay of the unstable clusters was examined. Overall, the contributions from secondary fragments do not greatly influence the spectral shapes and specifically the location of the spectral peaks are not significantly shifted down in energy due to the presence of these secondary fragments. Therefore contrary to the suggestion of Charity et al. [Phys. Rev. C 56, 873 (1997)], the lower peak energy of the experimental $\ensuremath{\alpha}$-particle spectrum as compared to standard statistical-model calculations cannot be attributed to sequential $\ensuremath{\alpha}$ particles from ${}^{5}\mathrm{He}$ and other clusters. Only for the extreme ``subbarrier'' regions of the $\ensuremath{\alpha}$-particle, deuteron, ${}^{6,7}\mathrm{Li},$ and ${}^{8}\mathrm{Be}$ spectra was the sequential contribution found to be dominant. Statistical-model calculations incorporating large initial deformations are shown to provide enhancements in the yield of low-energy fragments which are roughly appropriate for all the detected isotopes. This suggests that the origin of the sub-barrier enhancements may be a result of evaporation from highly deformed systems which are either produced dynamically during the fusion process or by thermal shape fluctuations.

Published
2001

37. Reaction mechanisms and multifragmentation processes in64Zn+58Niat35A–79A MeV

Author

E. Rosato, Th Keutgen, Ph. Eudes, K. Hagel, C. Lebrun, J.C. Steckmeyer, J. Cibor, J. C. Angelique, S. C. Jeong, J. B. Natowitz, D. Cussol, A. Auger, D. Durand, A. Péghaire, R. Wada, Edilson Crema, J.P. Patry, R. Regimbart, Michael D. Murray, Y. El Masri, M. Gonin, A. Kerambrum, R. Brou, Z.Y. He, G. Bizard, E. Vient, Jean Péter, C. Cabot, B. Tamain, F. Saint-Laurent, and Akira Ono

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Projectile, Nuclear Theory, Monte Carlo method, Kinetic energy, 01 natural sciences, 7. Clean energy, Charged particle, Thermal expansion, Spectral line, Nuclear physics, Molecular dynamics, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Reaction mechanisms and multifragmentation processes have been studied for Zn-64 + Ni-58 collisions at intermediate energies with the help of antisymmetrized molecular dynamics (AMD-V) model calculations. Experimental energy spectra, angular distributions, charge distributions, and isotope distributions, classified by their associated charged particle multiplicities, are compared with the results of the AMD-V calculations. In general the experimental results are reasonably well reproduced by the calculations. The multifragmentation observed experimentally at all incident energies is also reproduced by the AMD-V calculations. A detailed study of AMD-V events reveals that, in nucleon transport, the reaction shows some transparency, whereas in energy transport the reaction is much less transparent at all incident energies studied here. The transparency in the nucleon transport indicates that. even for central collisions, about 75% of the projectile nucleons appear in the forward direction. In energy transport about 80% of the initial kinetic energy of the projectile in the center-of-mass frame is dissipated. The detailed study of AMD-V events also elucidates the: dynamics of the multifragmentation process. The study suggests that, at 35A MeV, the semitransparency and thermal expansion are the dominant mechanisms for the multifragmentation process, whereas at 49A MeV and higher incident energies a nuclear compression occurs at an early stage of the reaction and plays an important role in the multifragmentation process in addition to that of the thermal expansion and the semitransparency.

Published
2000

38. Dynamic evolution and the caloric curve for medium mass nuclei

Author

J. Cibor, N. Marie, W. Q. Shen, Bao-An Li, M. Murray, J. B. Natowitz, Y. Zhao, M. Lunardon, P. Staszel, K. Hagel, R. Wada, B. Xiao, R. Alfaro, J. Li, Z. Majka, Cyclotron institute, and Cyclotron Institute

Subjects
Coalescence (physics), Physics, Nuclear and High Energy Physics, Heavy ions collisions, 010308 nuclear & particles physics, Projectile, Nuclear Theory, 25.70.Pq, Light particle, Coalescence model, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Caloric curve, Nuclear physics, 0103 physical sciences, Atomic physics, 010306 general physics, Nuclear Experiment, Excitation
Abstract

International audience; Self-consistent coalescence model analyses of light particle emission have been used to follow the evolution of the temperatures and densities of A≈110 nuclei produced in violent collisions induced by four different 47 AMeV projectiles. The degree of expansion of the emitting system increases with increasing projectile mass. The caloric curve derived for these expanding A≈110 nuclei plateaus near T=7 MeV. The plateau extends from 3.5 to 6.9 MeV/u excitation energy.

Published
2000

39. Experimental determination of fragment excitation energies in multifragmentation events

Author

M.F. Rivet, J.F. Lecolley, R. Bougault, C. Volant, Ph. Buchet, J. Colin, Marie Germain, R. Legrain, D. Guinet, G. Tabacaru, J. B. Natowitz, A. Chbihi, M. Assenard, E. Rosato, J.C. Steckmeyer, Ch.O. Bacri, A. Le Fèvre, Z. Majka, J.D. Frankland, J.L. Charvet, D. Gourio, Bernard Borderie, Ph. Eudes, J. Cibor, E. Gerlic, E. Genouin-Duhamel, D. Doré, A. Demeyer, D. Durand, L. Gingras, F. Bocage, G. Auger, S. Salou, E. Plagnol, J.P. Wieleczko, O. Tirel, T. Reposeur, M. Parlog, E. Vient, R. Brou, K. Hagel, A.D. Nguyen, D. Cussol, A. Rahmani, O. Lopez, N. Le Neindre, R. Wada, B. Tamain, A. M. Maskay, F. Saint-Laurent, T. Lefort, E. Galichet, M. Stern, L. Nalpas, R. Dayras, J.L. Laville, Jean Péter, Nathalie Marie, P. Lautesse, and M. Louvel

Subjects
Thermal equilibrium, Physics, Nuclear and High Energy Physics, Excited state, Atomic number, Atomic physics, Nuclear Experiment, Kinetic energy, Nucleon, Isotopes of helium, Charged particle, Excitation, Nuclear Physics
Abstract

For 50 MeV/nucleon {sup 129}Xe+{sup nat}Sn multifragmentation events, we deduced, by means of correlation techniques, the multiplicities of the hydrogen and helium isotopes which were emitted by the hot primary excited fragments produced at the stage of the disassembly of an equilibrated hot source. We also derived the relative kinetic energy distributions between the primary clusters and the light charged particles that they evaporate. From the comparison between the secondary multiplicities observed experimentally and the multiplicities predicted by the GEMINI model, we concluded that the source breaks into primary fragments which are characterized by the same N/Z ratio as the combined system. Knowing the secondary light charged particle multiplicities and kinetic energies, we reconstructed the average charges of the hot fragments and we estimated their mean excitation energies. The fragment excitation energies are equal to 3.0 MeV/nucleon for the full range of intermediate mass fragment atomic number. This global constancy indicates that, on the average, thermodynamical equilibrium was achieved at the disassembly stage of the source. {copyright} {ital 1998} {ital The American Physical Society}

Published
1998

40. Light particle probes of expansion and temperature evolution: Coalescence model analyses of heavy ion collisions at 47A MeV

Author

Z. Majka, R. Alfaro, P. Staszel, WQ（沈文庆） Shen, J. Cibor, B. Xiao, M. Lunardon, R. Wada, J. B. Natowitz, K. Hagel, N. Marie, M. Murray, T. Keutgen, Aldo Bonasera, Y. Zhao, J. Li, B. A. Li, Cyclotron institute, Cyclotron Institute, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), School of Earth Sciences [Bristol], University of Bristol [Bristol], and Guesnon, Sandrine

Subjects
Coalescence (physics), Nuclear reaction, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Projectile, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Spectral line, Charged particle, 25.70.Mn, 24.10.Lx, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment, Excitation
Abstract

The reactions C-12 + Sn-116, Ne-22 + Ag, Ar-40 + Mo-100, and Zn-64 + Y-89 have been studied at 47A MeV projectile energy. For these reactions the most violent collisions lend to increasing amounts of fragment and light particle emission as the projectile mass increases. This is consistent with quantum molecular dynamics (QMD) model simulations of the collisions. Moving source fits to the light charged particle data have been used to gain a global view of the evolution of the particle emission,Comparisons of the multiplicities and spectra of light charged particles emitted in the reactions with the four different projectiles indicate a common emission mechanism for early emitted ejectiles even though the deposited excitation energies differ greatly. The spectra for such ejectiles can be characterized as emission in the nucleon-nucleon frame. Evidence that the He-3 yield is dominated by this type of emission and the role of the collision dynamics in determining the H-3/He-3 yield ratio are discussed. Self-consistent coalescence model analyses are applied to the light cluster yields, in an attempt to probe emitter source sizes and to follow the evolution of the temperatures and densities from the time of first particle emission to equilibration. These analyses exploit correlations between ejectile energy and emission time, suggested by the QMD calculations. In this analysis the degree of expansion of the emitting system is found to increase with increasing projectile mass. The double isotope yield ratio temperature drops as the system expands. Average densities as low as 0.36 rho(0) are reached at a time near 100 fm/c after contact. Calorimetric methods were used to derive the mass and excitation energy of the excited nuclei which are present after preequilibrium emission. The derived masses range from 102 to 116 u and the derived excitation energies increase from 2.6 to 6.9 MeV/nucleon with increasing projectile mass. A caloric curve is derived for these expanded A similar to 110 nuclei. This caloric curve exhibits a plateau at temperatures near 7 MeV. The plateau extends from similar to 3.5 to 6.9 MeV/nucleon excitation energy.

41. How to calibrate the time scale of emission of intermediate mass fragments

Author

Wilczynski, J, DE FILIPPO, E, Pagano, A, Amorini, F, Anzalone, A, Auditore, Lucrezia, Baran, V, Berceanu, I, Blicharska, J, Brzychczyk, J, Bonasera, A, Borderie, B, Bogault, R, Bruno, M, Cardella, G, Cavallaro, S, Chatterjee, Mb, Chbihi, A, Cibor, J, Colonna, M, D'Agostino, M, Dayras, R, DI TORO, M, Frankland, J, Galichet, E, Gawlikowicz, W, Geraci, E, Giustolisi, F, Grzeszczuk, A, Guazzoni, P, Guinet, D, IACONO MANNO, M, Kowalski, S, LA GUIDARA, E, Lanzano, G, Lanzalone, G, LE NEINDRE, N, Li, S, Maiolino, C, Majka, Z, Papa, M, Petrovici, M, Piasecki, E, Pirrone, S, Planeta, R, Politi, G, Pop, A, Porto, F, Rivet, Mf, Rosato, E, Rizzo, F, Russo, S, Russotto, P, Sassi, M, Schmidt, K, SIWEK WILCZYNSKA, K, Skwira, I, Sperduto, Ml, Swiderski, L, Trifiro', Antonio, Trimarchi, Marina, Vannini, G, Vigilante, M, Wieleczko, Jp, Wu, H, Xiao, Z, Zetta, L, Zipper, W., Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CHIMERA, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), J. WILCZYNSKI, E. DE FILIPPO, A. PAGANO, F. AMORINI, A. ANZALONE, L. AUDITORE, V. BARAN, I. BERCEANU, J. BLICHARSKA, J. BRZYCHCZYK, A. BONASERA, B. BORDERIE, R. BOGAULT, M. BRUNO, G. CARDELLA, S. CAVALLARO, M.B. CHATTERJEE, A. CHBIHI, J. CIBOR, M. COLONNA, M. D'AGOSTINO, R. DAYRAS, M. DI TORO, J. FRANKLAND, E. GALICHET, W. GAWLIKOWICZ, E. GERACI, F. GIUSTOLISI, A. GRZESZCZUK, P. GUAZZONI, D. GUINET, M. IACONO-MANNO, S. KOWALSKI, E. LA GUIDARA, G. LANZANO, G. LANZALONE, N. LE NEINDRE, S. LI, C. MAIOLINO, Z. MAJKA, M. PAPA, M. PETROVICI, E. PIASECKI, S. PIRRONE, R. P LANETA, G. POLITI, A. POP, F. PORTO, M.F. RIVET, E. ROSATO, F. RIZZO, S. RUSSO, P. RUSSOTTO, M. SASSI, K. SCHMIDT, K. SIWEK-WILCZYNSKA, I. SKWIRA, M.L. SPERDUTO, L. SWIDERSKI, A. TRIFIRO', M. TRIMARCHI, G. VANNINI, M. VIGILANTE, J.P. WIELECZKO, H. WU, Z. XIAO, L. ZETTA, W. ZIPPER, J., Wilczynski, E., De Filippo, A., Pagano, F., Amorini, A., Anzalone, L., Auditore, V., Baran, I., Berceanu, J., Blicharska, J., Brzychczyk, A., Bonasera, B., Borderie, R., Bougault, M., Bruno, G., Cardella, S., Cavallaro, M. B., Chatterjee, A., Chbihi, J., Cibor, M., Colonna, M., D'Agostino, R., Dayra, M., Di Toro, J. D., Frankland, E., Galichet, W., Gawlikowicz, E., Geraci, F., Giustolisi, A., Grzeszczuk, P., Guazzoni, D., Guinet, M., Iacono Manno, S., Kowalski, E., La Guidara, G., Lanzanò, G., Lanzalone, N., Le Neindre, S., Li, C., Maiolino, Z., Majka, M., Papa, M., Petrovici, E., Piasecki, S., Pirrone, R., Planeta, G., Politi, A., Pop, F., Porto, M. F., Rivet, F., Rizzo, Rosato, Elio, S., Russo, P., Russotto, M., Sassi, K., Schmidt, K., Siwek Wilczynska, I., Skwira, M. L., Sperduto, L., Swiderski, A., Trifirò, M., Trimarchi, G., Vannini, Vigilante, Mariano, J. P., Wieleczko, H., Wu, Z., Xiao, L., Zetta, and W., Zipper

Subjects
COLLISIONS, REAZIONI SEMI-PERIFERICHE, Nuclear and High Energy Physics, Scale (ratio), multifragmentation, Nuclear Theory, General Physics and Astronomy, Time sequence, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, 0103 physical sciences, 010306 general physics, Nuclear Experiment, emission time scale, REAZIONI NUCLEARI FRA IONI PESANTI, Physics, 010308 nuclear & particles physics, Settore FIS/01 - Fisica Sperimentale, FISSION, nucleus-nucleus collision, TEMPI DI EMISSIONE DEI FRAMMENTI, PRODUZIONE DI FRAMMENTI, CORRELAZIONI IN VELOCITA' RELATIVA, Nucleon
Abstract

In order to obtain information on the time sequence and time scale of the production of intermediate mass fragments (IMF) in nucleus-nucleus collisions at intermediate energies it is proposed to analyze correlations between relative velocities of IMF's with respect to projectile-like fragments (PLF) and target-like fragments (TLF). Experimental data on the production of IMF's in the 124Sn+64Ni reaction, taken with the CHIMERA multidetector array at 35 MeV/nucleon, have been analyzed with the proposed method. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0218301305003119?prevSearch=%5BContrib%3A+rosato%5D&searchHistoryKey=

Published
2004

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