Factorial cumulants of proton multiplicity near a critical point using maximum entropy freeze-out prescription

2025/10/07 by Karthein, Jamie, Pradeep, Maneesha, Rajagopal, Krishna +2
#FOS: Physical sciences #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.2510.05567

Abstract

We present the first application of the maximum-entropy freeze-out prescription to calculate factorial cumulants of proton multiplicities near the conjectured QCD critical point in thermal equilibrium. We map the Gibbs free energy of the 3D Ising model to a parameterized class of possible EoS near QCD critical point. This equilibrium baseline highlights how factorial cumulants isolate critical fluctuations by subtracting trivial self-correlations, setting the stage for future out-of-equilibrium analyses. We identify the key non-universal aspects of the mapping to the Ising model that strongly control the characteristic properties, such as magnitude and location of the peaks of the factorial cumulants along the freeze-out curve.

Citations

• Proton cumulants from hydrodynamics in light of new STAR data
• Lattice-based equation of state with 3D Ising critical point

Related

• Quantifying fluctuation signatures of the QCD critical point using maximum entropy freeze-out
• Equilibrium expectations for non-Gaussian fluctuations near a QCD critical point
• Freezing out critical fluctuations
• Static critical fluctuations on the freeze-out surface
• Locating the QCD critical point from first principles through contours of constant entropy density