Effective model for in-medium $\bar{K}N$ interactions including the $L=1$ partial wave

TL;DR

This paper develops an extended coupled channels model based on chiral Lagrangian to explicitly include the $ ext{Σ}(1385)$ resonance, improving the understanding of in-medium $ar{K}N$ interactions and their effects on nuclear matter properties.

Contribution

The model explicitly incorporates the $ ext{Σ}(1385)$ resonance into the coupled channels framework, providing a unified treatment of $ ext{Λ}(1405)$ and $ ext{Σ}(1385)$ in nuclear medium.

Findings

Model accurately reproduces vacuum scattering data.

Nuclear matter significantly alters the $ ext{π} ext{Σ}$ mass spectrum.

Energy dependence of $K^{-}p$ branching ratios is affected in medium.

Abstract

Coupled channels model of meson-baryon interactions based on the effective chiral Lagrangian is extended to account explicitly for the $\Sigma(1385)$ resonance that dominates the $P$-wave $\bar{K}N$ and $\pi\Sigma$ interactions at energies below the $\bar{K}N$ threshold. The presented model aims at a uniform treatment of the $\Lambda(1405)$ and $\Sigma(1385)$ dynamics in the nuclear medium. We demonstrate the applicability of the model by confronting its predictions with the vacuum scattering data, then we follow with discussing the impact of nuclear matter on the $\pi\Sigma$ mass spectrum and on the energy dependence of the $K^{-}p$ branching ratios.