Binding of Hypernuclei in the Latest Quark-Meson Coupling Model

TL;DR

This paper advances the quark-meson coupling model by including the in-medium scalar field effect on hyperfine interactions, improving hypernuclei property predictions and aligning with experimental observations, especially for $oldsymbol{ ext{Σ}}$ hypernuclei.

Contribution

It introduces a self-consistent inclusion of the mean scalar field's effect on hyperfine interactions in the QMC model, refining hypernuclei predictions.

Findings

$ ext{Λ}$ and $ ext{Ξ}$ hypernuclei properties match previous results.

$ ext{Σ}$ hypernuclei are predicted to be unbound, consistent with experiments.

The $ ext{Σ}$ potential is repulsive inside nuclei and weakly attractive at the surface.

Abstract

The most recent development of the quark-meson coupling (QMC) model, in which the effect of the mean scalar field in-medium on the hyperfine interaction is also included self-consistently, is used to compute the properties of finite hypernuclei. The calculations for $\Lambda$ and $\Xi$ hypernuclei are of comparable quality to earlier QMC results without the additional parameter needed there. Even more significantly, the additional repulsion associated with the increased hyperfine interaction in-medium completely changes the predictions for $\Sigma$ hypernuclei. Whereas in the earlier work they were bound by an amount similar to $\Lambda$ hypernuclei, here they are unbound, in qualitative agreement with the experimental absence of such states. The equivalent non-relativistic potential felt by the $\Sigma$ is repulsive inside the nuclear interior and weakly attractive in the nuclear surface, as suggested by the analysis of $\Sigma$-atoms.