Beyond mean-field approach to heavy-ion reactions around the Coulomb barrier

TL;DR

This paper introduces a stochastic mean-field approach to better understand dissipation and fluctuations in heavy-ion reactions near the Coulomb barrier, improving variance predictions over traditional mean-field models.

Contribution

It extends the microscopic mean-field framework by incorporating stochastic elements to accurately describe fluctuations in heavy-ion collision observables.

Findings

Improved variance prediction of fragment mass distribution.

Fluctuations align with empirical semiclassical analysis.

Mean values of macroscopic variables show semiclassical breakdown below Coulomb barrier.

Abstract

Dissipation and fluctuations of one-body observables in heavy-ion reactions around the Coulomb barrier are investigated with a microscopic stochastic mean-field approach. By projecting the stochastic mean-field dynamics on a suitable collective path, transport coefficients associated with the relative distance between colliding nuclei and a fragment mass are extracted. Although microscopic mean-field approach is know to underestimate the variance of fragment mass distribution, the description of the variance is much improved by the stochastic mean-field method. While fluctuations are consistent with the empirical (semiclassical) analysis of the experimental data, concerning mean values of macroscopic variables the semiclassical description breaks down below the Coulomb barrier.