Constraining the symmetry energy with heavy-ion collisions and Bayesian analyses

Abstract

Efficiency corrected single ratios of neutron and proton spectra in central Sn112+112Sn and Sn124+124Sn collisions at 120 MeV/u are combined with double ratios to provide constraints on the density and momentum dependencies of the isovector mean-field potential. Bayesian analyses of these data reveal that the isoscalar and isovector nucleon effective masses, ms ⁎−mv ⁎ are strongly correlated. The linear correlation observed in ms ⁎−mv ⁎ yields a nearly independent constraint on the effective mass splitting Δmnp ⁎=(mn ⁎−mp ⁎)/mN=−0.05−0.09 +0.09δ. The correlated constraint on the standard symmetry energy, S0 and the slope, L at saturation density yields the values of symmetry energy S(ρs)=16.8−1.2 +1.2 MeV at a sensitive density of ρs/ρ0=0.43−0.05 +0.05. © 2019 The Authors