Energy and Centrality dependence of $dN_{\rm ch}/d\eta$ and $dE_{\rm T}/d\eta$ in Heavy-Ion Collisions from $\sqrt{s_{\rm NN}}$ =7.7 GeV to 5.02 TeV

TL;DR

This study analyzes how charged particle density and transverse energy vary with collision centrality and energy in heavy-ion collisions from 7.7 GeV to 5.02 TeV, using a two-component model to distinguish soft and hard particle production.

Contribution

It introduces a comprehensive analysis of energy and centrality dependence across a wide energy range, highlighting the energy independence of the hard component and challenges in understanding deformed nucleus collisions.

Findings

Hard component shows no clear energy dependence from RHIC to LHC.

Centrality and energy effects factor out with some species dependence.

Deformed nuclei collisions challenge energy-centrality factorization.

Abstract

The centrality dependence of pseudorapidity density of charged particles and transverse energy is studied for a wide range of collision energies for heavy-ion collisions at midrapidity from 7.7 GeV to 5.02 TeV. A two-component model approach has been adopted to quantify the soft and hard components of particle production, coming from nucleon participants and binary nucleon-nucleon collisions, respectively. Within experimental uncertainties, the hard component contributing to the particle production has been found not to show any clear collision energy dependence from RHIC to LHC. The effect of centrality and collision energy in particle production seem to factor out with some degree of dependency on the collision species. The collision of Uranium-like deformed nuclei opens up new challenges in understanding the energy-centrality factorization, which is evident from the centrality dependence of transverse energy density, when compared to collision of symmetric nuclei.