Neutron and proton spectra from the decay of Lambda hypernuclei

Abstract

We have determined the spectra of neutrons and protons following the decay of Λ hypernuclei through the one- and two-nucleon-induced mechanisms. The momentum distributions of the primary nucleons are calculated and a Monte Carlo simulation is used to account for final state interactions. The shape of the proton spectrum is sensitive to the value of Γ n / Γ 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 calculate the number of neutrons ( N n ) and protons ( N p ) per Λ decay and show how the measurement of these quantities, particularly N p , can lead to a determination of Γ n / Γ p . We also show that the consideration of the two-nucleon-induced channel has a repercussion on the results, widening the band of allowed values of Γ n / Γ p with respect to what is obtained neglecting this channel.