The elusiveness of multifragmentation footprints in 1-GeV proton-nucleus reactions

TL;DR

This study investigates whether signatures of multifragmentation are detectable in 1-GeV proton-nucleus reactions, finding that current observables do not provide clear evidence for multifragmentation and models favor sequential binary decays.

Contribution

It evaluates the sensitivity of physical observables to multifragmentation in proton-nucleus reactions using hybrid models, highlighting the difficulty in identifying unambiguous multifragmentation signatures.

Findings

No observable unambiguously indicates multifragmentation.

Experimental data favor sequential binary decay models.

Models fail to reproduce certain velocity distributions.

Abstract

We use the tools of hybrid intranuclear-cascade/nuclear-de-excitation models to evaluate the sensitivity of several physical observables to the inclusion of a multifragmentation stage in the de-excitation chain and assess the need for a multifragmentation model in the quantitative description of p+56Fe and p+136Xe reactions at 1-GeV incident energy. We seek clear signatures of multifragmentation by comparing different state-of-the-art de-excitation models coupled with intranuclear-cascade models and by focusing on discriminating observables such as correlations and fragment longitudinal-velocity distributions. None of the considered observables can be unambiguously interpreted as a multifragmentation footprint. The experimental data are best described as originating from sequential binary decays. However, no de-excitation model can reproduce the experimental longitudinal-velocity distributions from 1-GeV p+136Xe.