Variation of nonequilibrium processes in p+Ni system with beam energy

TL;DR

This study investigates how various nonequilibrium processes in proton-Ni collisions vary with beam energy, revealing differences in particle emission mechanisms at energies below 1 GeV.

Contribution

It provides new insights into the energy dependence of multiple nonequilibrium processes in proton-induced nuclear reactions at sub-GeV energies.

Findings

Identification of multiple nonequilibrium processes including coalescence, fireball emission, and target break-up.

Observation of significant differences in these processes at different beam energies.

Extraction of total production cross sections for various ejectiles.

Abstract

The energy and angular dependence of double differential cross sections dsigma/dOmega dE were measured for p, d, t, 3,4He, 6,7Li, 7,9Be, and 10,11B produced in collisions of 0.175 GeV protons with Ni target. The analysis of measured dfferential cross sections allowed to extract total production cross sections for ejectiles listed above. The shape of the spectra and angular distributions indicate the presence of other nonequilibrium processes besides the emission of nucleons from the intranuclear cascade, and besides the evaporation of various particles from remnants of intranuclear cascade. These nonequilibrium processes consist of coalescence of nucleons into light charged particles during the intranuclear cascade, of the fireball emission which contributes to the cross sections of protons and deuterons, and of the break-up of the target nucleus which leads to the emission of intermediate mass fragments. All such processes were found earlier at beam energies 1.2, 1.9, and 2.5 GeV for Ni as well as for Au targets, however, significant differences in properties of these processes at high and low beam energy are observed in the present study.