Correlation effects on the nonmesonic weak decay of the Λ hyperon in nuclear matter

Abstract

The nonmesonic weak decay of a \ensuremath{\Lambda} hyperon is studied in nuclear matter. Special emphasis is placed on a consistent treatment of correlations introduced by the strong interaction on its weak counterpart. The latter is described by the exchange of mesons between the initial $\ensuremath{\Lambda}N$ state and the final NN one. The weak decay is studied in terms of the weak self-energy, which allows a systematic evaluation of short-range and tensor correlation effects that are determined by a realistic hyperon-nucleon interaction. The admixture of $\ensuremath{\Sigma}N$ components through the strong interaction is also included in the calculation of the \ensuremath{\Lambda} decay properties. Calculations for the ratio of the neutron-induced partial width to the corresponding proton-induced one, ${\ensuremath{\Gamma}}_{n}/{\ensuremath{\Gamma}}_{p}$, are discussed in connection with recent experimental results.