Predictions for multiplicities and flow harmonics in 5.44 TeV Xe+Xe collisions at the CERN Large Hadron Collider

TL;DR

This paper provides next-to-leading-order predictions for particle multiplicities and flow harmonics in Xe+Xe collisions at 5.44 TeV, offering insights into the system's properties and comparison with Pb+Pb collisions.

Contribution

It introduces detailed theoretical predictions for multiplicities and flow harmonics in Xe+Xe collisions, highlighting their dependence on collision centrality and system size.

Findings

Predicted charged multiplicity at 0-5% centrality: 1218 ± 46.

Flow harmonics v2, v3, v4 show system-size and centrality dependence.

Flow harmonic ratios are sensitive to shear-viscosity-to-entropy ratio.

Abstract

We present the next-to-leading-order event-by-event EKRT model predictions for the centrality dependence of the charged hadron multiplicity in the pseudorapidity interval $|\eta|\le 0.5$, and for the centrality dependence of the charged hadron flow harmonics $v_n\{2\}$ obtained from 2-particle cumulants, in $\sqrt{s_{NN}}=5.44$ TeV Xe+Xe collisions at the CERN Large Hadron Collider. Our prediction for the 0-5 \% central charged multiplicity is $dN_{\rm ch}/d\eta =1218\pm 46$. We also predict $v_n\{2\}$ in Xe+Xe collisions to increase more slowly from central towards peripheral collisions than those in a Pb+Pb system. We find that at $10 \dots 50$\% centralities $v_2\{2\}$ is smaller and $v_3\{2\}$ is larger than in the Pb+Pb system while $v_4\{2\}$ is of the same magnitude in both systems. We also find that the ratio of flow harmonics in Xe+Xe collisions and in Pb+Pb collisions shows a slight sensitivity to the temperature dependence of the shear-viscosity-to-entropy ratio. As we discuss here, the new nuclear mass-number systematics especially in the flow harmonics serves as a welcome further constraint for describing the space-time evolution of a heavy-ion system and for determining the shear viscosity and other transport properties of strongly interacting matter.