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Correlations between emission timescale of fragments and isospin dynamics in $^(124)$Sn+$^(64)$Ni and $^(112)$Sn+$^(58)$Ni reactions at 35 AMeV
De Filippo E., Pagano A., Russotto P., Amorini F., Anzalone A. et al
Physical Review C 86 (2012) 014610 - http://hal.in2p3.fr/in2p3-00704236
Physique/Physique Nucléaire Expérimentale
Correlations between emission timescale of fragments and isospin dynamics in $^{124}$Sn+$^{64}$Ni and $^{112}$Sn+$^{58}$Ni reactions at 35 AMeV
E. De Filippo, A. Pagano, P. Russotto, F. Amorini, A. Anzalone, L. Auditore, V. Baran, I. Berceanu, B. Borderie1, R. Bougault2, M. Bruno, T. Cap, G. Cardella, S. Cavallaro, M. B. Chatterjee, A. Chbihi3, M. Colonna, M. D'Agostino, R. Dayras4, M. Di Toro, J. Frankland3, E. Galichet1, W. Gawlikowicz, E. Geraci, A. Grzeszczuk, P. Guazzoni, S. Kowalski, E. La Guidara, G. Lanzalone, G. Lanzanò, N. Le Neindre2, I. Lombardo, C. Maiolino, M. Papa, E. Piasecki, S. Pirrone, R. Planeta, G. Politi, A. Pop, F. Porto, M. F. Rivet1, F. Rizzo, E. Rosato, K. Schmidt, K. Siwek-Wilczynska, I. Skwira-Chalot, A. Trifirò, M. Trimarchi, G. Verde, M. Vigilante, J. P. Wieleczko3, J. Wilczynski, L. Zetta, W. Zipper
1 :  IPNO - Institut de Physique Nucléaire d'Orsay
CNRS : UMR8608 – IN2P3 – Université Paris XI - Paris Sud
IPN - 15, rue Georges Clemenceau - 91406 ORSAY CEDEX
2 :  LPCC - Laboratoire de Physique Corpusculaire de Caen
CNRS : UMR6534 – IN2P3 – Université de Caen Basse-Normandie – Ecole Nationale Supérieure d'Ingénieurs de Caen
ENSICAEN - 6, boulevard du Marechal Juin 14050 Caen Cedex
3 :  GANIL - Grand Accélérateur National d'Ions Lourds
Bvd Henri Becquerel - BP 55027 - 14076 CAEN CEDEX 5
4 :  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
Dynamique et thermodynamique nucléaire
We present a new experimental method to correlate the isotopic composition of intermediate mass fragments (IMF) emitted at mid-rapidity in semi-peripheral collisions with the emission timescale: IMFs emitted in the early stage of the reaction show larger values of $<$N/Z$>$ isospin asymmetry, stronger angular anisotropies and reduced odd-even staggering effects in neutron to proton ratio $<$N/Z$>$ distributions than those produced in sequential statistical emission. All these effects support the concept of isospin "migration", that is sensitive to the density gradient between participant and quasi-spectator nuclear matter, in the so called neck fragmentation mechanism. By comparing the data to a Stochastic Mean Field (SMF) simulation we show that this method gives valuable constraints on the symmetry energy term of nuclear equation of state at subsaturation densities. An indication emerges for a linear density dependence of the symmetry energy.

Articles dans des revues avec comité de lecture
Physical Review C (Phys. Rev. C)
Publisher American Physical Society
ISSN 0556-2813 (eISSN : 1089-490X)

GANIL 2012-082 A
25.70.Mn, 25.70.Pq
17 pages, 7 figures; The experiment was performed at the INFN-LNS Super-Conducting Cyclotron of Catania (Italy)
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