The balance of attractive and repulsive hadronic interactions: the influence of hadronic spectrum and excluded volume effects on lattice thermodynamics and consequences on experiments

TL;DR

This paper investigates how repulsive and attractive hadronic interactions, influenced by the hadronic spectrum and excluded volume effects, impact lattice QCD thermodynamics and experimental particle yields.

Contribution

It introduces parameterisations of repulsive interactions to extract effective hadron sizes from lattice QCD data, revealing size differences between strange and light hadrons.

Findings

Strange hadrons are systematically smaller than light hadrons with the same mass.

A simple repulsive interaction model can accurately fit lattice QCD data.

The model also reproduces experimental yields from ALICE and STAR.

Abstract

Repulsive hadronic interactions play a relevant role in the QCD dynamics, attractive ones being represented by resonance formation. In this study we propose different schemes in order to parameterise repulsive interactions, then being able to extract effective sizes of hadrons from fits to lattice QCD simulations. We find that allowing a difference between the strange and light sectors, strange particles are systematically smaller than light ones with equal mass. The very simple implementation of repulsive interactions would in principle allow to extract precise information about all hadronic species once corresponding lattice observables, sensitive to the species of interest, are provided. With the parameterisation which best reproduces lattice data there is also a good description of experimental yields measured by ALICE and STAR experiments.