Self-consistent propagation of hyperons and antikaons in nuclear matter based on relativistic chiral SU(3) dynamics

Abstract

We evaluate the antikaon spectral density in isospin symmetric nuclear matter. The in-medium antikaon–nucleon scattering process and the antikaon propagation is treated in a self-consistent and relativistic manner by performing a partial density resummation in terms of the free-space antikaon–nucleon scattering amplitudes. The latter amplitudes are taken from a covariant and chiral coupled-channel SU(3) approach which includes s-, p- and d-waves systematically. Particular care is taken on the proper evaluation of the in-medium mixing of the partial waves. Our analysis establishes a rich structure of the antikaon spectral function with considerable strength at small energies. At nuclear saturation density we predict attractive mass shifts for the Λ(1405), Σ(1385) and Λ(1520) of about 60 MeV, 60 MeV and 100 MeV, respectively. The hyperon states are found to exhibit at the same time an increased decay width of about 120 MeV for the s-wave Λ(1405), 70 MeV for the p-wave Σ(1385) and 90 MeV for the d-wave Λ(1520) resonance.