Multifragmentation in Relativistic Heavy-Ion Reactions

Abstract

Multifragmentation is the dominant decay mode of heavy nuclear systems with excitation energies in the vicinity of their binding energies. It explores the partition space associated with the number of nucleonic constituents and it is characterized by a multiple production of nuclear fragments with intermediate mass.Reactions at relativistic bombarding energies, exceeding several hundreds of MeV per nucleon, have been found very efficient in creating such highly excited systems. Peripheral collisions of heavy symmetric systems or more central collisions of mass asymmetric systems produce spectator nuclei with properties indicating a high degree of equilibration. The observed decay patterns are well described by statistical multifragmentation models.The present experimental and theoretical studies are particularly motivated by the fact that multifragmentation is being considered a possible manifestation of the liquidgas phase transition in finite nuclear systems. From the simultaneous measurement of the temperature and of the energy content of excited spectator systems a caloric curve of nuclei has been obtained. The characteristic S-shaped behavior resembles that of ordinary liquids.Signatures of critical phenomena in finite nuclear systems are searched for in multifragmentation data. These studies, supported by the success of percolation in reproducing the experimental mass or charge correlations, concentrate on the fluctuations observed in these observables. Attempts have been made to deduce critical-point exponents associated with multifragmentation.

Experimental investigation of the residues produced in the136Xe+Pband124Henzlová1, Schmidt2, Ricciardi3 et al. 2008Phys. Rev. C562480View full textAdd to dashboardCite

“…A considerable amount of excitation energy [8] and a slight momentum transfer [9] are induced, but compression is small. Thus, peripheral heavy-ion collisions at relativistic energies are ideal scenario for studying multifragment decay due to purely thermal instabilities [10], avoiding compression effects.…”