Fluctuations in heavy ion collisions and global conservation effects

TL;DR

This paper introduces the subensemble acceptance method (SAM) to correct for global conservation effects in heavy-ion collision fluctuations, providing new measures that are insensitive to these effects, applicable across various equations of state.

Contribution

The paper presents a general correction method for cumulants in heavy-ion collisions accounting for global conservation laws, applicable to arbitrary equations of state.

Findings

Derived formulas for cumulant corrections using SAM.

Introduced fluctuation measures insensitive to conservation effects.

Illustrated results with hadron resonance gas and van der Waals models.

Abstract

Subensemble is a type of statistical ensemble which is the generalization of grand canonical and canonical ensembles. The subensemble acceptance method (SAM) provides general formulas to correct the cumulants of distributions in heavy-ion collisions for the global conservation of all QCD charges. The method is applicable for an arbitrary equation of state and sufficiently large systems, such as those created in central collisions of heavy ions. The new fluctuation measures insensitive to global conservation effects are presented. The main results are illustrated in the hadron resonance gas and van der Waals fluid frameworks.