Pion absorption in He4 above the delta resonance

The reaction He-4(pi+, pp)pn was measured at T(pi) = 500 MeV. The angular distribution of quasifree two-body absorption which was obtained agrees in detail with the free pid --> pp reaction and scales according to the number of T = 0 pn pairs in He-4. Possible evidence for pd final-state interactions is discussed. The extrapolated total cross section for four-body absorption is 2.5 +/- 0.6 mb, which is substantially less than predicted from a model based on DELTADELTA excitation.