Constraining resonance properties through kaon production in pion-nucleus collisions at low energies

TL;DR

This study uses pion-nucleus collision data at low energies to constrain resonance properties and decay channels in hadronic transport models, improving understanding of baryonic resonances and kaon production mechanisms.

Contribution

It compares two transport models, SMASH and UrQMD, to experimental data, revealing how resonance decay channels and scattering angular distributions influence particle spectra.

Findings

Data favor lower momentum particle production in resonance decays.

Kaon rapidity distribution shape depends on elastic scattering angular distribution.

Model parameters can be constrained using differential spectra.

Abstract

Hadronic interactions are crucial for the dynamical description of heavy-ion reactions at low collision energies and in the late dilute stages at high collision energies. In particular, the properties and decay channels of resonances are an essential ingredient of hadronic transport approaches. The HADES collaboration measured particle production in collisions of pions with carbon and tungsten nuclei at $E_\text{kin} = 1.7\,\text{GeV}$. Such reactions are of high interest, because they allow to probe the properties of baryonic resonances produced in a much cleaner environment than the usual nucleus-nucleus collisions. We study these reactions with two transport approaches: SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) and UrQMD (Ultra relativistic Quantum Molecular Dynamics) which follow the same underlying concept but with different implementations. The differential spectra in rapidity and transverse momentum are used to show how model parameters, as the decay channels of high mass resonances and angular distributions of kaon elastic scattering, can be constrained. It is found that the data favor the production of more particles with lower momentum over the production of few particles with higher momentum in these decays. In addition, the shape of the rapidity distribution of the kaons strongly depends on the angular distribution of the elastic kaon-nucleon cross section.