Transverse momentum broadening of heavy quark and gluon energy loss in Sakai-Sugimoto model

TL;DR

This paper calculates the transverse momentum diffusion coefficient and gluon penetration length in the Sakai-Sugimoto holographic model, revealing differences from N=4 super-Yang-Mills theory and suggesting experimental tests at the LHC.

Contribution

It provides the first calculation of transverse momentum broadening and gluon penetration length in the Sakai-Sugimoto model, a holographic dual of large N_c QCD, highlighting model-dependent differences.

Findings

kappa_T proportional to lambda*gamma^{1/3}*T^4/T_d

delta x proportional to E^{2/5}

Differences from N=4 super-Yang-Mills results

Abstract

In this paper, we calculate the transverse momentum diffusion coefficient kappa_T of heavy quark and gluon penetration length in the deconfinement phase of Sakai-Sugimoto model, which is known as a holographic dual of large N_c QCD. We find that for the heavy quark moving through the thermal plasma with a constant velocity v<1, the transverse momentum diffusion coefficient kappa_T is proportional to lamda*gamma^{{1/3}}*T^4/T_d, and the gluon penetration length delta x is proportional to E^{{2/5}}. These results are different from those calculated in N=4 super-Yang-Mills theory, where kappa_T is proportional to lambda*gamma^{{1/2}}*T^3 and delta x is proportional to E^{{1/3}}, respectively. In the high energy limit, the difference between the two pairs of results should be evident, so we expect that the future LHC experiments can tell us which model is more closely related to the realistic strongly coupled QCD at finite temperature.