Non-mesonic weak decay of Λ hypernuclei within a nuclear matter framework

The non-mesonic weak decay of Λ hypernuclei is studied using nuclear matter. We have developed a formalism which gives a microscopic interpretation of the process of emission of particles originated in this decay. More specifically, our scheme provides a unified treatment of Γ(ΛN→NN) and NN (NNN), the Λ non-mesonic weak decay widths and the number of emitted particles (pair of particles) of kind N (NN), respectively. We have also evaluated for the first time the quantum interference terms between the n- and p-induced weak decay amplitudes. Explicit expressions for NN and NNN are shown within the ring approximation. Using the local density approximation together with the ring approximation, we report results for the decay of the hypernucleus. We have obtained values for the ratio Nn/Np (Nnn/Nnp) in the range 1.4–1.6 (0.2–0.3), where no energy threshold have been employed. The n- and p-induced interference terms modify in less than ∼3% these results.