Influence of anisotropic $\Lambda/\Sigma$ creation on the $\Xi^-$ mutiplicity in subthreshold proton-nucleus collisions

TL;DR

This paper investigates how anisotropic hyperon creation affects $ ext{Xi}^-$ baryon production in subthreshold proton-nucleus collisions, introducing a new production mechanism and matching experimental data.

Contribution

It proposes a novel mechanism involving secondary hyperon-nucleon interactions and demonstrates its impact on $ ext{Xi}^-$ multiplicity in transport model simulations.

Findings

Reproduces experimental $ ext{Xi}^-$ multiplicity and ratios

Shows sensitivity of $ ext{Xi}^-$ production to hyperon angular distribution

Highlights importance of secondary hyperon interactions in subthreshold collisions

Abstract

We present an analysis of $\Xi^-$ baryon production in subthreshold proton--nucleus ($p+A$) collisions in the framework of a BUU type transport model. We propose a new mechanism for $\Xi$ production in the collision of a secondary $\Lambda$ or $\Sigma$ hyperon and a nucleon from the target nucleus. We find that the $\Xi^-$ multiplicity in $p+A$ collisions is sensitive to the angular distribution of hyperon production in the primary $N+N$ collision. Using reasonable assumptions on the unknown elementary cross sections we are able to reproduce the $\Xi^-$ multiplicity and the $\Xi^-/(\Lambda+\Sigma^0)$ ratio obtained in the HADES experiment in $p$+Nb collisions at $\sqrt{s_{NN}} = $ 3.2 GeV energy.