Binding energy shifts from heavy-ion experiments in a nuclear statistical equilibrium model

Abstract

Chemical constants extracted from $^{124}$Xe+ $^{124}$Sn collisions at 32 AMeV are compared to the predictions of an extended nuclear statistical equilibrium model including mean-field interactions and in-medium binding energy shifts for the light ($Z\le 2$) clusters. The ion species and density dependence of the in-medium modification is directly extracted from the experimental data. We show that the shift increases with the mass of the cluster and the density of the medium, and we provide a simple linear fit for future use in astrophysical simulations in the framework of the CompOSE data base. The resulting mass fractions are computed in representative thermodynamic conditions relevant for supernova and neutron star mergers. A comparison to the results of a similar analysis of the same data performed in the framework of a relativistic mean-field model shows a good agreement at low density, but significant discrepancies close to the Mott dissolution of clusters in the dense medium.