Hyperon-nucleon interaction in chiral effective field theory at next-to-next-to-leading order

TL;DR

This paper develops a hyperon-nucleon potential within chiral effective field theory up to next-to-next-to-leading order, accurately describing scattering data and hypernuclear properties while accounting for SU(3) symmetry breaking.

Contribution

It introduces a novel regularization scheme and extends chiral EFT to the hyperon-nucleon sector at NNLO, including SU(3) symmetry breaking effects.

Findings

Excellent fit to low-energy scattering data

Analysis of new J-PARC hyperon-nucleon data

Predictions for hypertriton and hypernuclear separation energies

Abstract

A hyperon-nucleon potential for the strangeness $S=-1$ sector ($\Lambda N$, $\Sigma N$) up to third order in the chiral expansion is presented. SU(3) flavor symmetry is imposed for constructing the interaction, however, the explicit SU(3) symmetry breaking by the physical masses of the pseudoscalar mesons and in the leading-order contact terms is taken into account. A novel regularization scheme is employed which has already been successfully used in studies of the nucleon-nucleon interaction within chiral effective field theory up to high orders. An excellent description of the low-energy $\Lambda p$, $\Sigma^- p$ and $\Sigma^+ p$ scattering data is achieved. New data from J-PARC on angular distributions for the $\Sigma N$ channels are analyzed. Results for the hypertriton and $A=4$ hyper-nuclear separation energies are presented. An uncertainty estimate for the chiral expansion is performed for selected hyperon-nucleon observables.