Two-nucleon mechanism for antiproton annihilation in nuclei

Abstract The annihilation probability of an antiproton inside a nucleus is evaluated via the p NN → N n π reaction. For that purpose the p N→( n +1)π reaction is started from and one of the pions is allowed to be virtual, carrying the appropriate energy and momentum to produce physical particle-hole excitations. The new mechanism proves to be very important: at nuclear densities around ϱ = 0.2 ϱ 0 it has about the same strength as the one-nucleon annihilation mechanism, and becomes much more important as the nuclear density increases. The repercussion of the new channel in the p -nucleus annihilation cross section is studied and its relevance in p atoms and p -nucleus elastic scattering is …