Heavy quark diffusion in perturbative QCD at next-to-leading order

Area of Science:

• High Energy Physics
• Quantum Chromodynamics (QCD)
• Plasma Physics

Background:

• Understanding the behavior of heavy quarks in hot QCD plasma is crucial for studying the properties of the quark-gluon plasma.
• Previous calculations were limited to leading-order approximations, necessitating higher-order corrections for improved accuracy.

Purpose of the Study:

• To compute the momentum diffusion coefficient of a heavy quark in a hot QCD plasma.
• To extend calculations to next-to-leading order in the weak-coupling expansion.
• To analyze the impact of soft, electric-scale gauge field physics on heavy quark diffusion.

Main Methods:

• Employed weak-coupling expansion to calculate the momentum diffusion coefficient.
• Incorporated interference between overlapping scatterings and soft gauge field physics.
• Utilized the hard thermal loop effective theory to treat relevant physics scales.

Main Results:

• Derived the next-to-leading order expression for the momentum diffusion constant in 3-color, 3-flavor QCD.
• The derived formula is kappa = 16pi/3alpha(s)(2)T(3)(ln1/g(s)+0.07428+1.9026 g(s)).
• Observed poor convergence of the perturbative expansion, suggesting limitations of the weak-coupling approach at this order.

Conclusions:

• The next-to-leading order corrections significantly impact the momentum diffusion coefficient.
• The poor convergence highlights the complexity of heavy quark interactions in hot QCD plasma.
• Further theoretical and/or lattice studies may be needed to fully understand these phenomena.