Exploring reaction mechanisms and their competition in ⁵⁸Ni+⁴⁸Ca collisions at e = 25 AMeV

Latest results concerning the study of central collisions in 58Ni+48Ca reactions
at Elab(Ni)=25 AMeV are presented. The experimental data, collected with the CHIMERA
4π device, have been analyzed in order to investigate the competition among different
reaction mechanisms for central collisions in the Fermi energy domain. The method
adopted to perform the centrality selection refers to the global variable “flow angle”, that
is related to the event shape in momentum space, as it is determined by the eigenvectors
of the experimental kinetic-energy tensor. The main features of the reaction products were
explored by using different constraints on some of the relevant observables, such as mass
and velocity distributions and their correlations. Much emphasis was devoted to the
competition between fusion-evaporation processes with subsequent identification of a
heavy residue and a prompt multifragmentation mechanism. The reaction mechanism was
simulated in the framework of transport theories (dynamical stochastic BNV calculations,
followed by sequential SIMON code) and further comparison with dynamical calculations
from transport model (QMD, CoMD) are in progress. Moreover, an extension of this
study taking into account for the light particles has been envisaged.