The A dependence and threshold behaviour of the inclusive (π ,2π) reaction for T=0 nuclei

Abstract

The author calculates the dependence of the energy-differential inclusive cross section for the ( pi ,2 pi ) reaction on the mass number A for N=Z nuclei up to A approximately 60. He also calculates the variations of this cross section near threshold, where the outgoing pions have almost zero energy. He finds a significant A dependence resulting from the dominance of the increase in number of active particles over the decrease of matrix element squared. The threshold behaviour is strongly affected by Coulomb distortions of the outgoing pions, and he finds a large difference between the ( pi +,2 pi +) and the ( pi +, pi - pi +) cases. The true absorption of final pions is also checked, and found to be of secondary importance. All cases are studied as a function of g', the Migdal spin-isospin parameter.