The impact of glasma on heavy flavor azimuthal correlations and spectra

TL;DR

This paper investigates how the early-stage glasma fields in heavy-ion collisions influence heavy quark correlations and spectra, revealing significant azimuthal decorrelation and modifications to transverse momentum distributions.

Contribution

It introduces a novel simulation of heavy quark transport in a classical glasma background, analyzing its impact on azimuthal correlations and spectra for the first time.

Findings

Large azimuthal decorrelation of heavy quark pairs due to glasma fields

Significant $p_T$-broadening effects on heavy quark spectra

Altered nuclear modification factor $R_{AA}$ for heavy quarks

Abstract

We study the phenomenological impact of the pre-equilibrium glasma initial stage of heavy-ion collisions on heavy quark azimuthal correlations and spectra. Using our numerical solver, we simulate the transport of heavy quark test particles in an SU(3) glasma background field. The glasma field equations are formulated using classical real-time lattice gauge theory, and the heavy quark dynamics are described by classical transport equations numerically solved using the colored particle-in-cell method. For the first time, the effect of the glasma stage on the azimuthal correlations of $c\overline{c}$ and $b\overline{b}$ pairs is studied. The resulting azimuthal width $\sigma_{\Delta\phi}$ exhibits a large and quick decorrelation due to the strong glasma fields. Further, we evaluate how the $p_T$-broadening in the glasma affects heavy quark $p_T$-spectra, which are initialized according to the Fixed-Order Next-to-Leading Logarithm (FONLL) heavy quark production calculation. The nuclear modification factor $R_{AA}$ is extracted for $c$ and $b$ quarks in the glasma and additional nuclear PDF effects accounting for gluon shadowing are included.