Charge radii of potassium isotopes in the RMF(BCS)* approach

TL;DR

This study uses the RMF(BCS)* approach to analyze potassium isotopes' charge radii, achieving good agreement with experimental data and highlighting the need for beyond mean field methods for certain isotopes.

Contribution

The paper applies the RMF(BCS)* ansatz to potassium isotopes, improving the description of charge radii and odd-even staggering compared to previous models.

Findings

Reproduces experimental charge radii well for most isotopes.

Identifies limitations in describing $^{50}$K and $^{48,52}$K with mean-field models.

Suggests deformation and beyond mean field studies are necessary for accurate modeling.

Abstract

We apply the recently proposed RMF(BCS)* ansatz to study the charge radii of the potassium isotopic chain up to $^{52}$K. It is shown that the experimental data can be reproduced rather well, qualitatively similar to the Fayans nuclear density functional theory, but with a slightly better description of the odd-even staggerings (OES). Nonetheless, both methods fail for $^{50}$K and to a lesser extent for $^{48,52}$K. It is shown that if these nuclei are deformed with a $\beta_{20}\approx-0.2$, then one can obtain results consistent with experiments for both charge radii and spin-parities. We argue that beyond mean field studies are needed to properly describe the charge radii of these three nuclei, particularly for $^{50}$K.