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Fluctuations and correlations of conserved charges in the Polyakov chiral SU(3) quark mean field model

Dhananjay Singh* and Arvind Kumar†

  • *Contact author: snaks16aug@gmail.com
  • †Contact author: kumara@nitj.ac.in
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Phys. Rev. D 114, 074004 – Published 1 October, 2026

DOI: https://doi.org/10.1103/6knj-rwl8

Abstract

We compute generalized susceptibilities of conserved charges in the Polyakov chiral SU(3) quark mean field (PCQMF) model with the fermion vacuum term. At μB=0  MeV, the calculation covers the diagonal χnB,Q,S through eighth order and all twelve independent fourth-order off-diagonal correlators. Extending to finite μB at μQ=μS=0, we compute χnB through eighth order, χnQ,S through fourth order, the second-order off-diagonals, all twelve fourth-order off-diagonal correlators, and the odd-order baryon susceptibilities χ1B, χ3B, χ5B. The calculation includes the vacuum term (vac=1) and is repeated for an independently refitted no-sea variant (vac=0). At μB=0  MeV, the chiral pseudocritical temperature is Tpc=170.5  MeV (vac=1) and 166.4 MeV (vac=0), while the Polyakov-loop deconfinement temperature is Tdec=144.4  MeV (vac=1) and 146.6 MeV (vac=0). In vac=1, the derivative −dΔl,s/dT of the subtracted chiral condensate develops an inflection near Tdec. Higher derivative orders resolve the chiral-deconfinement splitting as twin maxima in χ4B and χ6Q, twin minima in χ8B and χ8Q, and multiple zero crossings in χ6B. Among the fourth-order off-diagonal correlators, vac=1 amplitudes exceed vac=0 in the baryon-charge channel across the chiral crossover. The baryon-strangeness, charge-strangeness, and mixed baryon-charge-strangeness components peak near the strange-melting temperature, where vac=0 dominates. Along Tpc(μB), the kurtosis ratio R42B≡χ4B/χ2B of vac=1 crosses zero at μB/Tpc≈2.15 for μQ=μS=0 and at ≈2.47 under the heavy-ion constraints of strangeness neutrality and nQ/nB=0.4, while vac=0 stays positive in both cases over μB≤500  MeV. The higher-order ratios R51B≡χ5B/χ1B and R62B≡χ6B/χ2B start negative in vac=1 and grow more negative as μB increases.

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Phys. Rev. D 114, 074004– Published 1 October, 2026
  • Received 10 June 2026
  • Accepted 11 September 2026
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