A measurement of the $\beta$-parameter in the charged nonleptonic decay of the $\Lambda^{0}$ hyperon

The authors obtain for the beta -parameter in the decay Lambda /sup 0/ to pi /sup -/p the value beta =-0.094+or-0.060. This value agrees with the theoretical prediction based on T-invariance and the mod Delta I mod =/sup 1///sub 2/ rule, taking into account the effects of final state interactions. The Lambda /sup 0/ were produced by 1.03 and 1.06 GeV/c pi /sup -/ in a liquid hydrogen target, and the polarization of the recoil proton was measured in a carbon-plate spark chamber polarimeter. The triggering conditions were successfully designed to select events of the configuration best adapted to the determination of the beta -parameter. (22 refs)