Evidence of Ni break-up from total production cross sections in p+Ni collisions

TL;DR

This study compares experimental total production cross sections in p+Ni collisions with a two-step model, revealing evidence of nuclear break-up processes especially for lighter reaction products.

Contribution

It provides evidence supporting the significance of nuclear break-up in proton-induced reactions on nickel, improving understanding of reaction mechanisms at energies up to 3 GeV.

Findings

Model accurately describes excitation function shapes.

Cross sections for heavy products are well reproduced.

Light product cross sections are underestimated, indicating break-up effects.

Abstract

The total production cross sections of light charged particles (LCPs), intermediate mass fragments (IMFs) and heavy reaction products of p+Ni collisions available in the literature have been compared with predictions of a two-step model in the proton beam energy range from reaction threshold up to approximately 3 GeV. Model cross sections were calculated assuming, that the reaction proceeds via an intranuclear cascade of nucleon-nucleon collisions followed by evaporation of particles from an equilibrated, heavy target residuum. The shape of the excitation functions was well described by model calculations for all reaction products. The magnitude of the cross sections was reasonably well reproduced for heavy reaction products, i.e. for nuclei heavier than Al, but the cross sections for lighter products were systematically underestimated. This fact was used as an argument in favor of a significant break-up contribution to the reaction mechanism. The present conclusions are supported by recently published results of investigations of differential cross sections in p+Ni collisions, which showed that hypothesis of the break-up of target nucleus is indispensable for a good reproduction of d2 sigma/dOmega dE for LCPs and IMFs.