Properties of the Nonmesonic Decay of the Λ Hyperon in Heavy Hypernuclei

The nonmesonic decay of the strange Λ particle in heavy hypernuclei is investigated. The experimentally determined Λ hyperon lifetime in the nuclear medium of τ_Λ = (145 ± 11) ps is used to extract information about the ΔI = 1/2 rule (valid for mesonic decay of kaons and hyperons) in case of the nonmesonic Λ decay. Using the model proposed in [1] we find that the ΔI = 1/2 rule seems to be violated for nonmesonic Λ decay.