The reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(${\pi }^{+}$,pp)p was measured at $T_{\pi }$=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 πd→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 T=1 (pn) pairs and the higher density of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ 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 ≊45% of the total absorption cross section, a larger fraction than reported previously below the (3,3) resonance. The three-body matrix element ‖$M_3$${\Vert }^2$ displays an angular dependence at both energies which is suggestive of initial-state interactions. No evidence of final-state interactions is seen.

• Received 20 January 1989

DOI:https://doi.org/10.1103/PhysRevC.40.1347