Quantifying fluctuation signatures of the QCD critical point using maximum entropy freeze-out

Fuente: arXiv
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Main Authors: Karthein, Jamie M., Pradeep, Maneesha Sushama, Rajagopal, Krishna, Stephanov, Mikhail, Yin, Yi
Format: Preprint
Published: 2025
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author Karthein, Jamie M.
Pradeep, Maneesha Sushama
Rajagopal, Krishna
Stephanov, Mikhail
Yin, Yi
author_facet Karthein, Jamie M.
Pradeep, Maneesha Sushama
Rajagopal, Krishna
Stephanov, Mikhail
Yin, Yi
contents A key question about the QCD phase diagram is whether there is a critical point somewhere on the boundary between the hadronic and quark-gluon plasma phases, and if so where. Heavy-ion collisions offer a unique opportunity to search for signatures of such a critical point by analyzing event-by-event fluctuations in particle multiplicities. To draw meaningful conclusions from experimental data, a theoretical framework is needed to link QCD thermodynamics with the particle spectra and correlations observed in detectors. The Equation of State (EoS) of QCD near a critical point can be related to the universal Gibbs free energy of the 3D Ising model using four currently unknown non-universal mapping parameters whose values are determined by the microscopic details of QCD. We utilize the maximum entropy approach to freeze-out the fluctuations in order to make estimates for factorial cumulants of proton multiplicities, assuming thermal equilibrium, for a family of EoS with a 3D Ising-like critical point, varying the microscopic inputs that determine the strength and structure of the critical features. We quantify the effect of the non-universal mapping parameters, and the distance between the critical point and the freeze-out curve, on the factorial cumulants of proton multiplicities.
format Preprint
id arxiv_https___arxiv_org_abs_2508_19237
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantifying fluctuation signatures of the QCD critical point using maximum entropy freeze-out
Karthein, Jamie M.
Pradeep, Maneesha Sushama
Rajagopal, Krishna
Stephanov, Mikhail
Yin, Yi
Nuclear Theory
High Energy Physics - Phenomenology
Nuclear Experiment
A key question about the QCD phase diagram is whether there is a critical point somewhere on the boundary between the hadronic and quark-gluon plasma phases, and if so where. Heavy-ion collisions offer a unique opportunity to search for signatures of such a critical point by analyzing event-by-event fluctuations in particle multiplicities. To draw meaningful conclusions from experimental data, a theoretical framework is needed to link QCD thermodynamics with the particle spectra and correlations observed in detectors. The Equation of State (EoS) of QCD near a critical point can be related to the universal Gibbs free energy of the 3D Ising model using four currently unknown non-universal mapping parameters whose values are determined by the microscopic details of QCD. We utilize the maximum entropy approach to freeze-out the fluctuations in order to make estimates for factorial cumulants of proton multiplicities, assuming thermal equilibrium, for a family of EoS with a 3D Ising-like critical point, varying the microscopic inputs that determine the strength and structure of the critical features. We quantify the effect of the non-universal mapping parameters, and the distance between the critical point and the freeze-out curve, on the factorial cumulants of proton multiplicities.
title Quantifying fluctuation signatures of the QCD critical point using maximum entropy freeze-out
topic Nuclear Theory
High Energy Physics - Phenomenology
Nuclear Experiment
url https://arxiv.org/abs/2508.19237