Confronting fluctuations of conserved charges in central nuclear collisions at the LHC with predictions from Lattice QCD

TL;DR

This study compares experimental fluctuations of conserved charges in high-energy nuclear collisions with Lattice QCD predictions, confirming the thermal nature of the created fireball and its properties near the QCD transition temperature.

Contribution

The paper demonstrates that experimental data on charge fluctuations in Pb-Pb collisions align with Lattice QCD results at the crossover temperature, supporting the thermal origin of the quark-gluon plasma.

Findings

Fluctuations match Lattice QCD predictions at T_c ≈ 155 MeV.

Data supports the thermalization of the fireball in heavy-ion collisions.

Results reinforce the QCD phase transition characteristics at high energy.

Abstract

We construct net baryon number and strangeness susceptibilities as well as correlations between electric charge, strangeness and baryon number from experimental data on the particle production yields at midrapidity of the ALICE Collaboration at CERN. The data were taken in central Pb-Pb collisions at $\sqrt{s_{\rm NN}}$~=~2.76~TeV and cover one unit of rapidity. We show that the resulting fluctuations and correlations are consistent with Lattice QCD results at the chiral crossover pseudocritical temperature $T_{c} \simeq$ 155 MeV. This agreement lends strong support to the assumption that the fireball created in these collisions is of thermal origin and exhibits characteristic properties expected in QCD at the transition from the quark gluon plasma to the hadronic phase. Since Lattice QCD calculations are performed at a baryochemical potential of $\mu_{B}$ = 0, the comparisons with LHC data are the most direct due to the vanishing baryon transport to midrapidity at these high energies.