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Main Authors: Zhao, Tianqi, Lin, Zidu, Kumar, Bharat, Steiner, Andrew W., Prakash, Madappa
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2406.05267
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author Zhao, Tianqi
Lin, Zidu
Kumar, Bharat
Steiner, Andrew W.
Prakash, Madappa
author_facet Zhao, Tianqi
Lin, Zidu
Kumar, Bharat
Steiner, Andrew W.
Prakash, Madappa
contents New measurements of the weak charge density distributions of $^{48}$Ca and $^{208}$Pb challenge existing nuclear models. In the post-PREX-CREX era, it is unclear if current models can simultaneously describe weak charge distributions along with accurate measurements of binding energy and charge radii. In this letter, we explore the parameter space of relativistic and non-relativistic models to study the differences between the electric and weak form factors, $ΔF=F_{ch}-F_{W}$, in $^{48}$Ca and $^{208}$Pb. We show, for the first time, which aspects of mean-field models are the most important in determining the relative magnitude of the neutron skin in lead and calcium nuclei. We carefully disentangle the tension between the PREX-2/CREX constraints and the ability of the RMF and Skyrme models to accurately describe binding energies and charge radii. We find that the nuclear symmetry energy coefficient $S_V$ and the isovector spin-orbit coefficient $b'_4$ play different roles in determining $ΔF$ of $^{48}$Ca and $^{208}$Pb. Consequently, adjusting $S_V$ or $b'_4$ shifts predicted $ΔF$ values toward or away from PREX-2/CREX measurements. Additionally, $S_V$ and the slope L are marginally correlated given the prior constraints of our Bayesian inference, allowing us to infer them separately from PREX-2/CREX data.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05267
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Characterizing the nuclear models informed by PREX and CREX: a view from Bayesian inference
Zhao, Tianqi
Lin, Zidu
Kumar, Bharat
Steiner, Andrew W.
Prakash, Madappa
Nuclear Theory
Solar and Stellar Astrophysics
New measurements of the weak charge density distributions of $^{48}$Ca and $^{208}$Pb challenge existing nuclear models. In the post-PREX-CREX era, it is unclear if current models can simultaneously describe weak charge distributions along with accurate measurements of binding energy and charge radii. In this letter, we explore the parameter space of relativistic and non-relativistic models to study the differences between the electric and weak form factors, $ΔF=F_{ch}-F_{W}$, in $^{48}$Ca and $^{208}$Pb. We show, for the first time, which aspects of mean-field models are the most important in determining the relative magnitude of the neutron skin in lead and calcium nuclei. We carefully disentangle the tension between the PREX-2/CREX constraints and the ability of the RMF and Skyrme models to accurately describe binding energies and charge radii. We find that the nuclear symmetry energy coefficient $S_V$ and the isovector spin-orbit coefficient $b'_4$ play different roles in determining $ΔF$ of $^{48}$Ca and $^{208}$Pb. Consequently, adjusting $S_V$ or $b'_4$ shifts predicted $ΔF$ values toward or away from PREX-2/CREX measurements. Additionally, $S_V$ and the slope L are marginally correlated given the prior constraints of our Bayesian inference, allowing us to infer them separately from PREX-2/CREX data.
title Characterizing the nuclear models informed by PREX and CREX: a view from Bayesian inference
topic Nuclear Theory
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2406.05267