Constraining equation of state of nuclear matter by charge-changing cross section measurements of mirror nuclei

TL;DR

This study introduces a new method to constrain the density dependence of nuclear symmetry energy, specifically the parameter L, by measuring charge-changing cross sections of mirror nuclei, providing a complementary approach to existing probes.

Contribution

The paper demonstrates a linear correlation between the symmetry energy parameter L and charge-changing cross section differences in mirror nuclei, incorporating pairing effects for accurate modeling.

Findings

Linear correlation between L and charge-changing cross section difference Δσ_cc.

Pairing effects are crucial for consistent correlation.

Method achieves similar precision as neutron skin or proton radius measurements.

Abstract

The nuclear symmetry energy plays a key role in determining the equation of state (EoS) of dense, neutron-rich matter, which connects the atomic nuclei with the hot and dense matter in universe, thus has been the subject of intense investigations in laboratory experiments, astronomy observations and theories. Various probes have been proposed to constrain the symmetry energy and its density dependence. Currently, the extensive data yield already a good and consistent constraint to the symmetry energy ($E_\text{sym}(\rho)$) at saturation density, but do not yet give a consistent result of one critical EoS parameter, $L$, the density dependence of the symmetry energy. In this work, we report a new probe of $L$ at saturation density. A good linear correlation is found between $L$ and the charge changing cross section difference ($\Delta\sigma_\text{cc}$) of mirror nuclei $^{30}$Si-$^{30}$S for both the Skyrme-Hartree-Fock theory (SHF) and covariant (relativistic) density functionals (CDF). We found that the pairing effect for this mirror pair is essential to get a consistent correlation between $L$ and $\Delta\sigma_\text{cc}$ in both the SHF and CDF. Here, the cross sections are calculated on the same target and at the same energy using the zero-range optical-limit Glauber model. The linearity is found to be in the same precision as those found between $L$ and neutron skin thickness or proton radius difference.