FIZIKA B 12 (2003)  1, 39 - 50

MULTI-FRAGMENT PRODUCTION IN THE ³²S+^58,64Ni REACTIONS AT 11 A MeV

F. GRAMEGNA^a, U. ABBONDANNO^b, A. BONASERA^c, M. BRUNO^d, G. CASINI^e, S. CAVALLARO^c,f, M. CHIARI^e, M. D'AGOSTINO^d, A. LANCHAIS^d, G. V. MARGAGLIOTTI^b, P. F. MASTINU^a, P. M. MILAZZO^b, A. MORONI^g, A. NANNINI^e, A. ORDINE^h, R. A. RICCI^a, F. TONETTO^b, L. TRAVAGLINI^a, G. VANNINI^d and L. VANNUCCI^a

^aIstituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Italy
^bIstituto Nazionale di Fisica Nucleare, Sezione di Trieste and Dipartimento di Fisica dell'Universita, Trieste, Italy
^cIstituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania, Italy
^dIstituto Nazionale di Fisica Nucleare, Sezione di Bologna and Dipartimento di Fisica dell'Universita, Bologna, Italy
^eIstituto Nazionale di Fisica Nucleare, Sezione di Firenze, Italy
^fDipartimento di Fisica dell'Universita, Catania, Italy
^gIstituto Nazionale di Fisica Nucleare, Sezione di Milano, Italy
^hIstituto Nazionale di Fisica Nucleare, Sezione di Napoli, Italy

Paper devoted to honour the memory of Professor Nikola Cindro

Received 27 June 2002;     revised manuscript received 26 February 2003
Accepted 10 March 2003        Online 20 September 2003

The characteristic features of the ³²S+^58,64Ni reaction at 11 A MeV have been investigated to evidence the possible rise of multi-fragmentation processes at low excitation energies. The importance of such phenomena consists in the fact that they could represent the signature of a nuclear phase transition from a liquid to a gas region. Evidence of multi-fragment production is displayed by the present data; even if the yield of such events is compatible with the predictions of statistical models, the partition of the mass of the decaying system cannot be easily reproduced. Some preliminary indications of isospin effects are suggested by looking at the differences between the two reacting systems.

PACS numbers: 25.70 Pq
UDC 539.172

Keywords: heavy ions, multi-fragmentation, nuclear phase transition

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