Net-Strangeness Fluctuations and Their Experimental Implications in the SU(3) PNJL Model Using the Subensemble Acceptance Method for the search of QCD Critical Point

TL;DR

This paper investigates net-strangeness fluctuations in the QCD phase diagram using the SU(3) PNJL model and the Subensemble Acceptance Method, aiming to identify signals of the critical end point through comparison with experimental data.

Contribution

It introduces a novel application of the Subensemble Acceptance Method to analyze acceptance effects on net-strangeness fluctuations within the SU(3) PNJL model.

Findings

Established a mapping between subvolume and total volume in fluctuation analysis.

Provided insights into how experimental acceptance influences net-strangeness fluctuation measurements.

Compared model results with STAR data and HRG model to assess the QCD critical point signals.

Abstract

The critical end point (CEP) is a key feature of the Quantum Chromodynamics (QCD) phase diagram, where critical phenomena cause higher-order moments of conserved charges net-baryon ($\Delta B$), net-charge ($\Delta Q$), and net-strangeness ($\Delta S$) to exhibit non-monotonic behavior. These moments and their volume-independent products are sensitive to the correlation length, making them crucial observables in the search for the CEP. In this study, we investigate net-strangeness fluctuations using the finite-volume Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model, incorporating six-quark and eight-quark interactions at energy scales relevant to the RHIC beam energy scan. Our results are compared to STAR net-kaon data and the Hadron Resonance Gas (HRG) model to assess the CEP's existence. Since direct measurement of conserved charges is experimentally challenging, net-proton, net-pion, and net-kaon are used as proxies for $\Delta B$, $\Delta Q$, and $\Delta S$. We employ the Subensemble Acceptance Method (SAM) to analyze the acceptance dependence of $\kappa\sigma^{2}$ for net-strangeness fluctuations. Our findings establish a direct mapping between the subvolume (particle fraction) and the total volume (conserved quantities), providing insights into the role of experimental acceptance in fluctuation measurements.