Chemical Freeze-Out and Higher Order Multiplicity Moments

Abstract

We calculate the non-normalized moments of the particle multiplicity within the framework of the hadron resonance gas (HRG) model. At finite chemical potential $\mu$, a non-monotonic behavior is observed in the thermal evolution of third order moment (skewness $S$) and the higher order ones as well. Among others, this observation likely reflects dynamical fluctuations and strong correlations. The signatures of non-monotonicity in the normalized fourth order moment (kurtosis $\kappa$) and its products get very clear. Based on these findings, we introduce a novel condition characterizing the universal freeze-out curve. The chemical freeze-out parameters $T$ and $\mu$ are described by vanishing $\kappa {\sigma }^2$ or equivalently $m_4=3{\chi }^2$, where $\sigma$, $\chi$ and $m_4$ are the standard deviation, susceptibility and fourth order moment, respectively. The fact that the HRG model is not able to release information about criticality related to the confinement and chiral dynamics should not veil the observations related to the chemical freeze-out. Recent lattice QCD studies strongly advocate the main conclusion of the present paper.

17 Pages, 5 Figures. arXiv admin note: substantial text overlap with arXiv:1205.1761

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Cited by in corpus (12)

• Equilibrium Statistical-Thermal Models in High-Energy Physics
• Constant Trace Anomaly as a Universal Condition for the Chemical Freeze-Out
• Polyakov linear SU(3) sigma model: features of higher order moments in dense and thermal hadronic medium
• Possible interrelations among chemical freezeout conditions
• Chemical freezeout parameters within generic nonextensive statistics
• Chemical freeze-out in Hawking-Unruh radiation and quark-hadron transition
• Hadron resonance gas with repulsive mean field interaction: Thermodynamics and transport properties
• Hadron resonance gas EoS and the fluidity of matter produced in HIC
• On SU(3) effective models and chiral phase-transition
• Deconfinement and freezeout boundaries in equilibrium thermal models
• Particle Ratios within EPOS, UrQMD and Thermal Models at AGS, SPS and RHIC Energies
• Strangeness chemical potential from the baryons relative to the kaons particle ratios