Mesonic and non-mesonic branching ratios of K− absorption in the nuclear medium

The branching ratios of K− absorption at rest in nuclear matter are evaluated from the K− self-energy by using the chiral unitary approach for the s-wave K¯N amplitude. We find that both the mesonic and non-mesonic absorption potentials are dominated by the Λ(1405) contributions. We also observe that the mesonic absorption ratio [π−Σ+]/[π+Σ−] increases as a function of nuclear density due to the interference between Λ(1405) and the I=1 non-resonant background, which is consistent with experimental results. The fraction of the non-mesonic absorption is evaluated to be about 30% at the saturation density. The branching ratios of the K− absorption at rest into deuteron and 4He are also calculated.