ReactionHe3(π+,pp)patTπ=350 and 500 MeV

The reaction {sup 3}He({pi}{sup +},{ital pp}){ital p} was measured at {ital T}{sub {pi}}=350 and 500 MeV in a kinematically complete experiment. Separate contributions from two-body and three-body pion absorption are clearly seen in recoil momentum distributions. The two-body angular distributions closely follow the shape of the free {pi}{ital d}{r arrow}{ital pp} cross section, although the number of deuterons estimated from the two-body yield is larger than the value 1.5 expected from isospin coupling and observed previously at lower energies. Comparison with a simple impulse approximation model suggests some of the enhancement may arise from binding of the quasideuteron, although absorption on {ital T}=1 ({ital pn}) pairs and the higher density of {sup 3}He may also be a factor. The strength of the three-body component falls off with bombarding energy with roughly the same slope as for the two-body component, and accounts for {approx}45% of the total absorption cross section, a larger fraction than reported previously below the (3,3) resonance. The three-body matrix element {vert bar}{ital M}{sub 3}{vert bar}{sup 2} displays an angular dependence at both energies which is suggestive of initial-state interactions. No evidence of final-state interactions is seen.