Density-dependent effective baryon-baryon interaction from chiral three-baryon forces

TL;DR

This paper constructs a density-dependent effective baryon-baryon interaction from chiral three-baryon forces, providing explicit formulas and numerical estimates relevant for hypernuclear matter calculations.

Contribution

It introduces a new method to derive density-dependent baryon interactions from chiral three-body forces, including explicit expressions and numerical estimates.

Findings

Moderate repulsion in Lambda-nucleon interaction increases with density.

Provides explicit in-medium Lambda-nucleon potential expressions.

Numerical estimates show the effect of three-body forces in nuclear matter.

Abstract

A density-dependent effective potential for the baryon-baryon interaction in the presence of the (hyper)nuclear medium is constructed, based on the leading (irreducible) three-baryon forces derived within SU(3) chiral effective field theory. We evaluate the contributions from three classes: contact terms, one-pion exchange and two-pion exchange. In the strangeness-zero sector we recover the known result for the in-medium nucleon-nucleon interaction. Explicit expressions for the Lambda-nucleon in-medium potential in (asymmetric) nuclear matter are presented. Our results are suitable for implementation into calculations of (hyper)nuclear matter. In order to estimate the low-energy constants of the leading three-baryon forces we introduce the decuplet baryons as explicit degrees of freedom and construct the relevant terms in the minimal non-relativistic Lagrangian. With these, the constants are estimated through decuplet saturation. Utilizing this approximation we provide numerical results for the effect of the three-body force in symmetric nuclear matter and pure neutron matter on the Lambda-nucleon interaction. A moderate repulsion that increases with density is found in comparison to the free Lambda-nucleon interaction.