Single- & double-strangeness hypernuclei up to A = 8 within χEFT

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 Λ separation energies BΛ in A = 3 − 5 hypernuclei when only SRG-evolved two-body and when both twoand 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. 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 ΛN channel, whose strength has been fitted to the presently established CSB in A = 4. Finally, we report on our recent study for Ξ hypernuclei based on the ΞN interaction at NLO.