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Lambda(1405) N to Y N transition in nuclear medium for non-mesonic absorption of Kbar in nucleus

Non-mesonic transition of Lambda(1405) N to YN is investigated as one of the essential processes for the non-mesonic absorption of Kbar in nuclei. Using one-meson exchange model in the calculation of the transition, we find that the non-mesonic transition ratio Gamma_{Lambda N} / Gamma_{Sigma N} depends strongly on the ratio of the Lambda(1405) (Lambda^*) couplings to Kbar N and pi Sigma. Especially a larger Lambda^*-Kbar N coupling leads to enhancement of the transition to Lambda N. Using the chiral unitary model for the description of the Lambda^*, we obtain Gamma_{Lambda N} / Gamma_{Sigma^{0} N} is approximately 1.2 which is almost independent of the nucleon density, and find the total non-mesonic decay width of the Lambda^* in uniform nuclear matter to be 22 MeV at the normal density.