Collision energy dependence in heavy ion collisions from nonlinear QCD evolution

TL;DR

This paper integrates nonlinear QCD evolution equations into the initial state modeling of heavy-ion collisions, revealing significant effects on observables and emphasizing the importance of energy dependence in understanding quark-gluon plasma formation.

Contribution

It introduces a novel approach by incorporating JIMWLK evolution into the IP-Glasma model, enhancing the description of nuclei at specific Bjorken-$x$ values across different energies.

Findings

Significant impact on multiplicity distributions and particle spectra.

Enhanced understanding of energy dependence in heavy-ion collision observables.

Framework for more accurate extraction of transport coefficients.

Abstract

We explore the effects of including the energy dependence determined from evolution equations within the color glass condensate framework on observables in ultra-relativistic heavy-ion collisions. This amounts to integrating the JIMWLK evolution equations into the IP-Glasma model, which is then coupled to viscous relativistic hydrodynamics. This methodology allows for a systematic representation of nuclei at specific Bjorken-$x$ values, which are probed at different center-of-mass energies of the collision and rapidities of final state particles. Comparing to the conventional IP-Glasma model, we find significant effects on multiplicity distributions and particle spectra, especially in smaller collision systems at the highest center of mass energies. Our results highlight the importance of incorporating nonlinear QCD evolution in the description of heavy ion collisions at varying center of mass energies, as the precise extraction of transport coefficients will be affected. This work establishes a robust framework for understanding the quark gluon plasma and nuclear structure at high energy, integrating small-$x$ physics into the initial conditions of heavy-ion collisions.