Density correlations under global and local charge conservation

Abstract

This work presents a formalism to compute spatial $n$-point correlations of a conserved charge density in a large thermal system in the canonical ensemble, with explicit results presented up to 4th order. The resulting correlators contain local and balancing terms expressed through the grand-canonical susceptibilities for any equation of state. The new formalism is used to introduce a Gaussian local baryon number conservation in (spatial) rapidity in heavy-ion collisions at LHC conditions through a modulation of the balancing term. Connection to the conservation volume $V_c$ approach is established, indicating that the latter is appropriate for observables within a limited range around midrapidity. Quantitative analysis of the experimental data of the ALICE Collaboration on net proton cumulants in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV shows significant evidence for local baryon conservation.

7 pages, 2 figures + supplemental material. Published version

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Cited by in corpus (2)

• Acceptance dependence of factorial cumulants, long-range correlations, and the antiproton puzzle
• Measurement of correlations among net-charge, net-proton, and net-kaon multiplicity distributions in Pb$-$Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV