Collision-Energy Dependence in Heavy-Ion Collisions from Nonlinear QCD Evolution.

Area of Science:

• High-energy nuclear physics
• Quantum Chromodynamics (QCD)
• Relativistic heavy-ion collisions

Background:

• The Color Glass Condensate (CGC) framework describes the high-energy limit of Quantum Chromodynamics.
• Understanding the initial conditions of ultrarelativistic heavy-ion collisions is crucial for studying the quark-gluon plasma.
• Existing models often simplify the energy dependence of nuclear wave functions.

Purpose of the Study:

• To investigate the impact of energy-dependent evolution equations on observables in heavy-ion collisions.
• To integrate the JIMWLAC (Jalilian-Mahan, Iancu, McLerran, Weigert, Leonhardt, and Kovner) evolution equations into the impact parameter-dependent glasma model.
• To establish a framework for high-energy nuclear structure and quark-gluon plasma studies.

Main Methods:

• Integration of the JIMWLAC evolution equations into the impact parameter-dependent glasma model.
• Coupling the modified glasma model with viscous relativistic hydrodynamics.
• Systematic representation of nuclei at specific Bjorken-x values probed at varying collision energies and particle rapidities.

Main Results:

• Significant effects observed on multiplicity distributions and particle spectra compared to conventional models.
• Discrepancies are particularly pronounced in smaller collision systems at the highest center-of-mass energies.
• Demonstrated the importance of nonlinear QCD evolution for describing heavy-ion collisions across different energies.

Conclusions:

• The inclusion of energy dependence from evolution equations is essential for accurate descriptions of heavy-ion collisions.
• Precise extraction of transport coefficients is sensitive to the chosen theoretical framework.
• This work provides a robust method for integrating small-x physics into the initial conditions of heavy-ion collisions.