Slope parameters determined from CREX and PREX2 (published in Results in Physics)

TL;DR

This paper analyzes recent measurements of neutron skin thickness from CREX and PREX2 experiments to determine the slope parameter L, revealing a significant discrepancy between the two results that challenges current understanding.

Contribution

It provides a comparative analysis of L derived from CREX and PREX2 skin measurements using a large set of equations of state, highlighting a notable inconsistency.

Findings

L(CREX) = 0-51 MeV

L(PREX2) = 76-165 MeV

No overlap between L values from CREX and PREX2

Abstract

[Background] Very lately, the CREX group presents a skin value $\Delta R_{\rm skin}^{48}({\rm CREX}) =0.121 \pm 0.026\ {\rm (exp)} \pm 0.024\ {\rm (model)}=0.071\sim 0.171$~fm. Meanwhile, the PREX group reported a skin value $\Delta R_{\rm skin}^{208}({\rm PREX2}) = 0.283\pm 0.071=0.212 \sim 0.354$~fm. In our previous paper, we determined both the $L$--$\Delta R_{\rm skin}^{48}$ relation and the $L$--$\Delta R_{\rm skin}^{208}$ one, using 206 EoSs, where $L$ is a slope parameter. [Purpose] We determine $L$ from $\Delta R_{\rm skin}^{48}({\rm CREX})$ and $\Delta R_{\rm skin}^{208}({\rm PREX2}) $, using 207 EoSs. [Results] The $\Delta R_{\rm skin}^{48}({\rm CREX})$ yields $L({\rm CREX})=0 \sim 51$~MeV and the $\Delta R_{\rm skin}^{208}({\rm PREX2}) $ does $L({\rm PREX2})=76 \sim 165$~MeV. [Conclusion] There is no overlap between $L({\rm CREX})$ and $L({\rm PREX2})$. This is a big problem to be solved.