Implications of an increased $\Lambda$-separation energy of the hypertriton

TL;DR

This paper investigates how a larger hypertriton binding energy affects hypernuclear interactions and binding energies, using chiral effective field theory and various computational methods, with implications for hypernuclear structure and interactions.

Contribution

It demonstrates that a more strongly bound hypertriton can be modeled within current data constraints, affecting hypernuclear binding energy predictions and interaction strengths.

Findings

Hypertriton separation energy can be increased within experimental bounds.

Predicted hypernuclear binding energies align better with empirical data.

The description of hypernuclear spectra remains consistent with increased hypertriton binding.

Abstract

Stimulated by recent indications that the binding energy of the hypertriton could be significantly larger than so far assumed, requirements of a more strongly bound $^3_\Lambda {\rm H}$ state for the hyperon-nucleon interaction and consequences for the binding energies of $A=4,5$ and $7$ hypernuclei are investigated. As basis a $YN$ potential derived at next-to-leading order in chiral effective field theory is employed, Faddeev and Yakubovsky equations are solved to obtain the corresponding $3$- and $4$-body binding energies, respectively, and the Jacobi no-core shell model is used for $^5_\Lambda$He and $^7_\Lambda$Li. It is found that the spin-singlet $\Lambda p$ interaction would have to be much more attractive which can be, however, accommodated within the bounds set by the available $\Lambda p$ scattering data. The binding energies of the $^4_\Lambda {\rm He}$ hypernucleus are predicted to be closer to the empirical values than for $YN$ interactions that produce a more weakly bound $^3_\Lambda {\rm H}$. The quality of the description of the separation energy and excitation spectrum for $^7_\Lambda$Li remains essentially unchanged.