Isospin effects and symmetry energy studies with INDRA

The equation of state of asymmetric nuclear matter is still controversial, as predictions at subsaturation as well as above normal density widely diverge. We discuss several experimental results measured in heavy-ion collisions with the INDRA array in the incident energy range 5-80 MeV/nucleon. In particular an estimate of the density dependence of the symmetry energy is derived from isospin diffusion results compared with a transport code: the potential part of the symmetry energy linearly increases with the density. We demonstrate that isospin equilibrium is reached in mid-central collisions for the two reactions Ni+Au at 52 MeV/nucleon and Xe+Sn at 32 MeV/nucleon. New possible variables and an improved modelization to investigate symmetry energy are discussed.Comment: Review for the special issue of EPJA on symmetry energy. 20 pages, 16 figure

The Fazia initiative: more powerful detectors for a more detailed investigation on the origin and the decay of charged fragments

International audienceThe main results of the R&D program of the FAZIA collaboration are described. The objective was to improve particle identication capabilities from solid-state telescopes made of Silicon detectors and CsI(Tl) scintillators in view of a new large acceptance apparatus to be used for heavy-ion physics. Important progresses have been made on silicon detectors thanks to a careful control of the material, of its doping uniformity and of the crystal orientation. Moreover, the use of appropriate fast digital electronics allowed to extract maximum information via Pulse Shape Analysis and to propose new configurations of CsI(Tl) readout. Some of the recent results of the telescopes are discussed here, together with some perspective and preliminary data on the physics program at intermediate bombarding energie

Multifragmentation in central collisions at intermediate energies: a fast process?

XL Bormi

Collective motion and kinetic energy fluctuations in central nuclear collisions studied with IN-DRA

ibide

Decay competition for IMF produced in the collisions 78Kr+40Ca and 86Kr+48Ca at 10 A.MeV

Decay modes of excited compound systems 118Ba and 134Ba, produced respectively in the 78Kr+40Ca and 86Kr+48Ca collisions at 10 A·MeV, are investigated. In particular, the competition between the various disintegration path of medium mass compound nuclei, formed by fusion processes, the production of the so referred Intermediate Mass Fragments (IMF), and the isospin dependence of the decay process are studied. Data were taken at the INFN-Laboratori Nazionali del Sud (LNS) by using the CHIMERA array. Data analysis is in progress; a first indication on the average-energy angular distributions suggests pre-equilibrium effects affecting the data and the presence of isotopical effects