Single- & double-strangeness hypernuclei up to $ A=8 $ within chiral effective field theory

TL;DR

This paper uses chiral effective field theory and the Jacobi-NCSM approach to study single- and double-strangeness hypernuclei up to mass number 8, analyzing the effects of SRG evolution and different potentials on binding energies and symmetry breaking.

Contribution

It provides a comprehensive analysis of hypernuclei using chiral EFT interactions, including SRG effects, phase-equivalent potentials, and CSB splittings, extending to $\Xi$ hypernuclei.

Findings

NLO19 potential reproduces experimental separation energies well.

SRG evolution impacts $\Lambda$ separation energies, especially when including three-body forces.

CSB splittings are studied in $A=7,8$ hypernuclei with fitted CSB potentials.

Abstract

We investigate $S=-1$ and $-2$ hypernuclei with $A=4-8$ employing the Jacobi-NCSM approach and in combination with baryon-baryon interactions derived within the frame work of chiral effective field theory. The employed interactions are transformed using the similarity renormalization group (SRG) so that the low- and high-momentum states are decoupled, and, thereby,convergence of the binding energies with respect to model space can be significantly speeded up. Such an evolution is however only approximately unitary when the so-called SRG induced higher-body forces are omitted. We first explore the impact of the SRG evolution on the $\Lambda$ separation energies $B_{\Lambda}$ in $A=3-5$ hypernuclei when only SRG-evolved two-body and when both two- and three-body forces are included. For the latter scenario, we thoroughly study predictions of the two almost phase-equivalent NLO13 and NLO19 YN potentials for $A=4-7$ hypernuclei. The NLO19 interaction yields separation energies that are comparable with experiment, whereas NLO13 underestimates all the systems considered. We further explore CSB splittings in the $A=7,8$ multiplets employing the two NLO YN potentials that include also the leading CSB potential in the $\Lambda$N channel, whose strength has been fitted to the presently established CSB in $A=4$. Finally, we report on our recent study for $\Xi$ hypernuclei based on the $\Xi$N interaction at NLO.