Exploring the density dependence of the symmetry energy with isotopic distributions

The properties of nuclear matter in the nucleonic regime are determined by the nuclear interaction, which is, in turn, uniquely linked to the nuclear equation of state (EOS). In spite of its key role in determining important properties of exotic nuclei and astrophysical objects such as neutron stars, the equation of state for asymmetric nuclear matter has relatively few constraints. In particular, the density dependence of the potential part of the symmetry energy term of the EOS represents one of the main challenges for the research activities in nuclear physics. The isotopic distributions of complex fragments produced in multifragmentation reactions at intermediate energies are expected to be a good observable to extract information. However surface effects could be important, as at saturation densities, leading to differences between the symmetry energy extracted from multifragmenting system and the infinite nuclear matter symmetry energy. Antisymmetrized Molecular Dynamics (AMD) calculations predict those effects to be negligible. To address this question, the INDRA-VAMOS Collaboration performed an experiment, coupling the 4π detector INDRA with the VAMOS spectrometer. The first experimental results and their comparison to AMD predictions will be presented in this contribution