Geometrical aspects of high-energy peripheral nucleus-nucleus collisions

Abstract

The abrasion-ablation model of relativistic nucleus-nucleus (heavy ion) fragmentation reactions is extended to mass number dependence and factorization properties of the cross sections. Weak (fragment-target) factorization is approximately valid while strong (projectile-target) factorization is violated. Calculated projectile-target factors γ PT for the fragmentation of 12C or 16O agree with the Berkeley and Orsay experiments. We propose using the fitted exponent y of the expression σ exp ∼(A P 1 3 + A T 1 3 ) y as a geometrical signature for discriminating peripheral and non-peripheral collisions for medium and heavy nuclei. The weak, logarithmic dependence of n-nucleon processes on the total nucleon-nucleon cross section σ NN implies weak beam energy dependence of fragmentation cross sections. A number of definite experimental predictions are made.