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

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.