Effective kaon masses in dense nuclear and neutron matter

Abstract

The effective mass and decay width of kaonic modes in baryonic matter are studied within a coupled-channel approach based on the Chiral SU(3) Effective Lagrangian which describes all available low energy data of the coupled K N, π∑, πΛ system. Including Pauli blocking and Fermi motion in the kaon dispersion relation, we find a strong non-linear density dependence of the K − effective mass and decay width in symmetric nuclear matter at densities around 0.1 times normal nuclear matter density ϱ 0 due to the in-medium dynamics of the Λ(1405) resonance. At higher densities the K − effective mass decreases slowly but stays above 0.5 m K at least up to densities below 3 ϱ 0. In neutron matter the K − effective mass decreases almost linearly with increasing density but remains relatively large ( m K ∗ > 0.65 m K ) for ϱ n ≲ 3 ϱ 0. The K + effective mass turns out to increase very slowly with rising density.