PI-MESONIC DECAY OF THE HYPERTRITON

The pi-mesonic decay of the hypertriton is calculated based on a hyper triton wave function and 3N scattering states, which are rigorous solu tions of three-body Faddeev equations using realistic NN and hyperon-n ucleon interactions. The total pi-mesonic decay rate is found to be 10 1% of the free Lambda decay rate, which is close to the experimental d ata. Together with the nonmesonic decay the total lifetime of H-3(Lamb da) is predicted to be 2.56 x 10(-10) sec which is 3% smaller than for the free Lambda particle. The differential decay rate is evaluated as a function of the pion momentum. The decay into the N + d + pi channe l is stronger than in the 3N + pi channel in contrast to the situation for the nonmesonic decay. The ratio for the decay rate into He-3 + pi (-) to the decay rate into all channels including pi(-) is found to be 0.379, which is close to the experimental value. We visualize the dec ay into the dominant channel p + d + pi(-) in a Dalitz plot. Finally w e compare the polarization of the outgoing proton in free unpolarized Lambda decay to the polarization of He-3 in unpolarized, H-3(Lambda) d ecay and we compare the closely related asymmetry of pi(-) emitted par allel and antiparallel with respect to the spin direction for a polari zed Lambda to the corresponding asymmetry for a polarized H-3(Lambda). [S0556-2813(98)01104-2].