Spectator fragmentation in nucleus-nucleus collisions: Phase space approach

TL;DR

This paper investigates the breakup of spectator matter in gold nucleus collisions at high energy using quantum molecular dynamics, comparing different clusterization algorithms to understand fragment production.

Contribution

It introduces the use of the simulated annealing clusterization algorithm (SACA) in QMD simulations, showing its effectiveness in predicting fragment yields.

Findings

SACA yields more projectile-like and target-like fragments.

Spatial correlation clusterization predicts fewer fragments.

Fragment origin traced back to initial contact time.

Abstract

Dynamics of spectator matter break-up in non-central collisions of $^{197}$Au+ $^{197}$Au at 1000 AMeV are explored within framework of quantum molecular dynamics (QMD) model. The phase space of nucleons bound in intermediate mass fragments are studied using two clusterization subroutines. Backtracking the origin of fragments to the time of initial contact between colliding nuclei indicates that \textit{simulated annealing clusterization algorithm} (SACA) results into significant yield of projectile-like and target-like fragments. Simplest clusterization approach based on spatial correlation technique, however, predicted much lesser production probability of fragments in spectator zone.