Theoretical shell-model signatures in heavy-ion, coherent pion production

Abstract

A comprehensive summary of a many-body, microscopic, particle–hole formalism is presented that describes coherent, subthreshold, pion production in peripheral, heavy-ion collisions. The formalism uses a new separable model transition interaction that produces Δ-hole states in either the projectile or target nucleus. Shell-model states described by harmonic oscillator functions are used in the calculation of Δ formation and decay and Lorentz-contraction effects of the nucleus not at rest are included. An analytical expression to lowest multipole order for the differential cross section is examined. The sensitivity of the theoretical results to the shell-model states is determined with preliminary shape results compared with data. The effects of higher multipoles are examined with attention paid to the second-order multipole value.