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 ($\mathrm{\Delta }{\sigma }_{\text{cc}}$) of mirror nuclei ³⁰Si-³⁰S 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 $\mathrm{\Delta }{\sigma }_{\text{cc}}$ 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.

核对称能在确定致密的富中子物质的状态方程（EoS）中起着关键作用，它将原子核与宇宙中炽热的致密物质联系起来，因此一直是实验室实验中深入研究的主题，天文学观测和理论。已经提出了各种探针来约束对称能量及其密度依赖性。目前，大量数据已经对对称能量产生了良好且一致的约束（${乙}_{\text{符号}}(\rho )$) 在饱和密度下，但尚未给出一个关键 EoS 参数 L 的一致结果，L是对称能量的密度依赖性。在这项工作中，我们报告了饱和密度下L的新探测。在L和电荷变化截面差之间发现了良好的线性相关性（$\mathrm{\Delta }{\sigma }_{\text{抄送}}$) 镜核³⁰ Si- ³⁰ S 用于 Skyrme-Hartree-Fock 理论 (SHF) 和协变（相对论）密度泛函 (CDF)。我们发现这个镜像对的配对效应对于获得L和$\mathrm{\Delta }{\sigma }_{\text{抄送}}$在 SHF 和 CDF 中。在这里，使用零范围光学极限 Glauber 模型在相同目标和相同能量下计算横截面。发现线性度与L和中子表皮厚度或质子半径差之间的线性度具有相同的精度。