Institut de recherche sur les lois fondamentales de l'Univers

Direction de la recherche fondamentale

Résumé du preprint DAPNIA-05-31

DAPNIA-05-31
Time sequence and time scale of intermediate mass fragments’emission
E. De Filippo, A. Pagano, J. Wilczynski, 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. 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. Planeta, 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, and W. Zipper.
Semiperipheral collisions in the 124Sn + 64Ni reaction at 35 MeV/nucleon were studied by using the forward part of the Charged Heavy Ion Mass and Energy Resolving Array (CHIMERA). Nearly completely determined ternary events involving projectile-like fragments (PLF), target-like fragments (TLF), and intermediate mass fragments (IMF) were selected. A new method of studying the reaction mechanism, focused 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 IMF�s. It is shown that the majority of light IMF�s are produced within 40-80 fm/c after the system starts to reseparate. Heavy IMF�s are formed at times of about 120 fm/c or later and can be viewed as resulting from two-step (sequential-like) neck rupture processes.

DAPNIA-05-31

Time sequence and time scale of intermediate mass fragments’emission

E. De Filippo, A. Pagano, J. Wilczynski, 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. 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. Planeta, 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, and W. Zipper.

Semiperipheral collisions in the 124Sn + 64Ni reaction at 35 MeV/nucleon were studied by using the forward part of the Charged Heavy Ion Mass and Energy Resolving Array (CHIMERA). Nearly completely determined ternary events involving projectile-like fragments (PLF), target-like fragments (TLF), and intermediate mass fragments (IMF) were selected. A new method of studying the reaction mechanism, focused 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 IMF�s. It is shown that the majority of light IMF�s are produced within 40-80 fm/c after the system starts to reseparate. Heavy IMF�s are formed at times of about 120 fm/c or later and can be viewed as resulting from two-step (sequential-like) neck rupture processes.