Burger, B.J.Beise, E.J.Gilad, S.Redwine, R.P.Roos, P.J.Chant, N.S.Breuer, H.Ciangaru, G.Silk, J.D.Blanpied, J.S.Preedom, B.M.Ritchie, B.G.Blecher, M.Gotow, K.Lee, D.M.The reaction 58Ni(π+,pp) was studied with good energy resolution for an incident pion energy of 160 MeV. The angular correlation of the outgoing protons was measured for θlab=30°, 75°, and 130°. From these angular correlations the contribution from direct two-nucleon absorption was extracted. A Monte Carlo calculation modeling the absorption process in terms of initial-state scattering of the pion before absorption, two-nucleon absorption, and final-state scattering of the outgoing nucleons is compared to the data. We conclude that within this framework the two-nucleon mechanism can account for less than half of the total absorption cross section in 58Ni. We report results for the low-energy coincidence proton spectra (down to 5 MeV) which suggest that most of these protons come from evaporation. Angular correlation data for the reaction 58Ni(π-,pp) are also presented.PhysicsPion energyArticle