Simple Solution to the Strangeness Horn Description Puzzle

TL;DR

This paper introduces a refined thermal model with variable hard-core radii for hadrons, successfully explaining the Strangeness Horn phenomenon across a wide energy range without compromising fit quality.

Contribution

It presents a novel multi-component hadron resonance gas model with adjustable radii, enabling a complete description of the Strangeness Horn and improving fit accuracy.

Findings

Optimal radii: pions zero, kaons 0.35 fm, others fixed.

Achieved a comprehensive fit of hadron yield ratios across energies.

Demonstrated potential to determine hadron-hadron interaction coefficients.

Abstract

We propose to use the thermal model with the multi-component hard-core radii to describe the hadron yield ratios from the low AGS to the highest RHIC energies. It is demonstrated that the variation of the hard-core radii of pions and kaons enable us to drastically improve the fit quality of the measured mid-rapidity data and for the first time to completely describe the Strangeness Horn behavior as the function of the energy of collision without spoiling the fit quality of other ratios. The best global fit is found for the vanishing hard-core radius of pions and for the hard-core radius of kaons being equal to 0.35 fm, whereas the hard-core radius of all other mesons is fixed to 0.3 fm and that one of baryons is fixed to 0.5 fm. It is argued that the multi-component hadron resonance gas model opens us a principal possibility to determine the second virial coefficients of hadron-hadron interaction.