Partial-wave expansion of $\Lambda NN$ three-baryon interactions in chiral effective field theory

TL;DR

This paper derives a more general partial wave expansion formula for three-baryon interactions in chiral effective field theory, facilitating detailed studies of hypernuclei and neutron-star matter.

Contribution

It provides a systematic and generalized expression for partial wave expansion of $ ext{Lambda} NN$ interactions, enabling advanced calculations of hypernuclear forces.

Findings

Derived a more general partial wave expansion formula.

Evaluated a $ ext{Lambda}$-deuteron folding potential.

Facilitates future Faddeev calculations for hypernuclei.

Abstract

An expression of partial wave expansion of three-baryon interactions in chiral effective field theory is presented. The derivation follows the method by Hebeler et al. [Phys. Rev. C{\bf 91}, 044001 (2015)], but the final expression is more general. That is, a systematic treatment of the higher-rank spin-momentum structure of the interaction becomes possible. Using the derived formula, a $\Lambda$-deuteron folding potential is evaluated. This information is valuable for inferring the possible contribution of the $\Lambda NN$ three-baryon forces to the hypertriton as the basis of further studies by sophisticated Faddeev calculations. A microscopic understanding of $\Lambda NN$ three-baryon forces together with two-body $\Lambda N$ interactions is essential for the description of hypernuclei and neutron-star matter.