NEUTRON AND PROTON SPECTRA FROM THE DECAY OF LAMBDA-HYPERNUCLEI

We have determined the spectra of neutrons and protons following the d ecay of Lambda hypernuclei through the one- and two-nucleon-induced me chanisms. The momentum distributions of the primary nucleons are calcu lated and a Monte Carlo simulation is used to account for final state, interactions. The shape of the proton spectrum is sensitive to the val ue of Gamma(n)/Gamma(p) the ratio of neutron- to proton-induced decay, and the available experimental information favors larger values than those predicted by the one-pion-exchange model. From the spectra we ca lculate the number of neutrons (N-n) and protons (N-p) per Lambda deca y and show how the measurement of these quantities, particularly N-p, can lead to a determination of Gamma(n)/Gamma(p). We also show that th e consideration of the two-nucleon-induced channel has a repercussion on the results, widening the band of allowed values of Gamma(n)/Gamma( p) with respect to what is obtained neglecting this channel.