Ground state normalization in the nonmesonic weak decay of ¹²_(Λ)C hypernucleus within a nuclear matter formalism

The nonmesonic weak decay width of $^{12}_{\Lambda}C$ hypernucleus has been evaluated within a nuclear matter formalism, using the local density approximation. In addition to the one-body induced decay $(\Lambda N \to n N)$, it has been also considered the two-body induced decay $(\Lambda NN \to n N N)$. This second decay is originated from ground state correlations, where a renormalization procedure to ensure a ground state normalized to one has been implemented. Our results show that the plain addition of the two-body induced decay implies a lost in the ground state-norm, which adds $\sim 38%$ of spurious intensity to the nonmesonic weak decay width. By an adequate selection of the $\Lambda N$-transition potential, our result for the nonmesonic weak decay width of $^{12}_{\Lambda}C$ is 0.956, in good agreement with the most recent data.