Mesonic and non-mesonic decay widths of Λ12C

Abstract

Results are reported on the precise measurement of the lifetime and the weak-decay branching ratios with charged particle( π − and proton) emission from Λ 12C formed via 12C( π +, K +) reaction. The π − mesonic decay width is consistent with the calculations including the pion wave function distortion effect. We observed large contribution of the neutron-stimulated decay widths, Γ( Λ + n → n + n), in the non-mesonic weak decay, which cannot be explained by the current theoretical calculations.