Fluctuating glasma initial conditions and flow in heavy ion collisions

Area of Science:

• High Energy Nuclear Physics
• Quantum Chromodynamics
• Condensed Matter Theory

Background:

• Understanding the initial state of heavy ion collisions is crucial for interpreting experimental results.
• The Color Glass Condensate (CGC) framework provides a theoretical basis for describing the dense, out-of-equilibrium state of matter formed in these collisions.
• Previous models often simplified the complex initial conditions, limiting predictive power.

Purpose of the Study:

• To compute initial conditions for heavy ion collisions within the CGC framework.
• To incorporate impact parameter dependence and quantum fluctuations of color charges into initial state models.
• To compare the predictions of this new model with experimental data on particle spectra and flow coefficients.

Main Methods:

• Combined the impact parameter dependent saturation model with classical Yang-Mills theory for Glasma fields.
• Included nucleon position fluctuations and quantum fluctuations of color charges.
• Utilized relativistic viscous hydrodynamic evolution to simulate collision outcomes.
• Analyzed transverse momentum spectra and anisotropic flow coefficients (v(2,3,4)) for pions.

Main Results:

• The model naturally produces initial energy fluctuations described by a negative binomial distribution.
• The ratio of triangularity to eccentricity (ε(3)/ε(2)) closely matches experimental observations.
• Transverse momentum spectra and flow coefficients from this model show good agreement with relativistic viscous hydrodynamic evolution results.

Conclusions:

• The developed model provides a more realistic description of initial conditions in heavy ion collisions.
• Incorporating quantum fluctuations and impact parameter dependence improves the accuracy of theoretical predictions.
• This framework offers a promising avenue for future studies of the Quark-Gluon Plasma.