Simulation of the reaction of fragmentation of deuterons into cumulative and twice-cumulative pions

The paper discusses the features of the behavior of pion production cross section as a function of the atomic mass of the target nucleus for the reaction of fragmentation of the incident deuterons in the pions produced in the so-called "twice-cumulative" kinematic region. A distinctive feature of the twice-cumulative pions is that for their production the target nucleus must be heavier than hydrogen. The simulation results show that the dependence of the cross sections for pion production in the twice-cumulative region differs from the analogous dependence for the cumulative region. The paper discusses the reasons for such differences. In this work we present simulation results for some models of nuclear structure on small nucleon-nucleon distances.