Transverse energy and charged particle production in heavy-ion collisions: From RHIC to LHC

TL;DR

This paper investigates charged particle and transverse energy production in heavy-ion collisions across a wide energy range, revealing a universal scaling behavior at nucleon and quark levels, and provides predictions for future LHC energies.

Contribution

It introduces a universal function combining logarithmic and power-law forms to describe particle production across all energies and participant types, advancing understanding of collision mechanisms.

Findings

Scaling behavior becomes centrality independent when normalized to participant quarks.

A universal function describes production at all energies and participant levels.

Predictions for LHC energies are provided and compared with existing models.

Abstract

We study the charged particle and transverse energy production mechanism from AGS, SPS, RHIC to LHC energies in the framework of nucleon and quark participants. At RHIC and LHC energies, the number of nucleons-normalized charged particle and transverse energy density in pseudorapidity, which shows a monotonic rise with centrality, turns out to be an almost centrality independent scaling behaviour when normalized to the number of participant quarks. A universal function which is a combination of logarithmic and power-law, describes well the charged particle and transverse energy production both at nucleon and quark participant level for the whole range of collision energies. Energy dependent production mechanisms are discussed both for nucleonic and partonic level. Predictions are made for the pseudorapidity densities of transverse energy, charged particle multiplicity and their ratio (the barometric observable, $\frac{dE_{\rm{T}}/d\eta}{dN_{\rm{ch}}/d\eta} ~\equiv \frac{E_{\rm{T}}}{N_{\rm{ch}}}$) at mid-rapidity for Pb+Pb collisions at $\sqrt{s_{\rm{NN}}}=5.5$ TeV. A comparison with models based on gluon saturation and statistical hadron gas is made for the energy dependence of $\frac{E_{\rm{T}}}{N_{\rm{ch}}}$.