Study of central collisions for the 58Ni + 40Ca system at 35 AMeV and the nuclear matter Equation of State

The study of nuclear multifragmentation plays a crucial role in understanding nuclear matter at densities lower than the saturation density. To this end, the reaction 58Ni + 40Ca at an incident energy of 35 AMeV was investigated within the framework of the THERMO experiment, conducted at the INFN-LNS. The experiment employed the superconducting cyclotron and the 4π CHIMERA multidetector. Owing to the distinctive features of the CHIMERA detector, it was possible to perform a detailed analysis of the properties of fragments emitted in central collisions. The experimental observables were compared with theoretical predictions obtained from a dynamical approach based on the Boltzmann-Langevin One-Body (BLOB) model. A particularly significant part of the analysis concerned the variation of the asymmetry-term parameter (asy-stiffness) entering the nuclear matter equation of state, with the aim of investigating, through comparison with experimental data, whether nuclear matter exhibits a soft or stiff behavior below saturation.