Constraining the $\hat{I}›\hat{I}›$ interaction with terrestrial and astronomical data

Abstract

Terrestrial double-$\hat{I}›$ hypernuclear data and astronomical observations of neutron stars provide complementary constraints on the $\hat{I}›\hat{I}›$ interaction. In this work, we investigate the $\hat{I}›\hat{I}›$ interaction within a Skyrme energy density functional framework based on the KIDS (Korea-IBS-Daegu-SKKU) models. We employ a Skyrme-type $\hat{I}›\hat{I}›$ interaction that includes the standard $s$- and $p$-wave terms, as well as a density-dependent term that effectively represents an $N\hat{I}›\hat{I}›$ three-body force. The $s$-wave terms are constrained using data on double-$\hat{I}›$ hypernuclei supplemented by pseudodata obtained from core + $2\hat{I}›$ three-body model calculations including heavier hypernuclei. We show that the data on heavier systems are essential to simultaneously constrain the two $s$-wave parameters. We further explore the impact of the $p$-wave and $N\hat{I}›\hat{I}›$ components on the neutron-star properties and find that appropriate repulsive contributions of these terms yield consistency with current neutron-star mass-radius observations. These results indicate that the present framework provides phenomenologically acceptable equations of state for dense $(N,\hat{I}›)$ matter over a wide range of densities and highlight the importance of future experimental data on heavier double-$\hat{I}›$ hypernuclei.

11 pages, 6 figures