Diagonal and off-diagonal susceptibilities of conserved quantities in relativistic heavy-ion collisions

TL;DR

This paper investigates second-order susceptibilities of conserved quantities in heavy-ion collisions using thermal and transport models, analyzing detector effects and proposing normalized susceptibilities as probes of the medium's properties at freezeout.

Contribution

It provides a comprehensive analysis of susceptibilities in heavy-ion collisions with new focus on detector acceptance effects and normalized observables for medium characterization.

Findings

Susceptibilities are sensitive to QCD phase transition signals.

Normalized susceptibilities depend on transverse momentum cutoffs.

Detector acceptance significantly influences measured susceptibilities.

Abstract

Susceptibilities of conserved quantities, such as baryon number, strangeness and electric charge are sensitive to the onset of quantum chromodynamics (QCD) phase transition and are expected to provide information on the matter produced in heavy-ion collision experiments. A comprehensive study of the second-order diagonal susceptibilities and cross correlations has been made within a thermal model approach of the hadron resonance gas (HRG) model as well as with a hadronic transport model, UrQMD. We perform a detailed analysis of the effect of detector acceptances and choice of particle species in the experimental measurements of the susceptibilities for heavy-ion collisions corresponding to \sNN = 4 GeV to 200 GeV. The transverse momentum cutoff dependence of suitably normalised susceptibilities are proposed as useful observables to probe the properties of the medium at freezeout.