Energy density of light quark jet using AdS/CFT

High Energy Particle Physics Workshop 2016

Morad, R.^1 ; Horowitz, W.A.^1

Department of Physics, University of Cape Town, Private Bag X3, Rondebosch

7701, South Africa^1

关键词: Coupled calculation;    Energy density distributions;    Energy-loss rate;    Energy-momentum tensor;    Expanding plasmas;    Heavy ion collision;    Initial conditions;    Nuclear modification factors;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/802/1/012009/pdf
DOI  :  10.1088/1742-6596/802/1/012009

来源: IOP

【 摘 要 】

We study the energy loss rate of light quarks via the AdS/CFT correspondence in both a static and an expanding plasma. Unlike heavy quarks, light quark energy loss in AdS/CFT is surprisingly dependent on both the string initial conditions and the very definition of the jet itself in the gravity theory. We aim to more closely match the string initial conditions to those expected from perturbative quantum chromodyanics (pQCD)-the theory known to describe the physics of high-momentum particles at early times in heavy ion collisions-by computing the energy-momentum tensor associated with the propagation of the classical string solution. The jet energy-momentum tensor in a strongly-coupled calculation can be found by a superposition of contributions from a collection of point particles whose paths approximate the evolution of the string world-sheet. My results show that some times after creation the pair of quark-anti quark, the energy density is not time dependent. This means that the corresponding jet does not lose energy and the associated nuclear modification factor would be one as expected. Also, the results reveal the virtuality dependency of energy density distribution over space. As expected, the energy of a more virtual jet is spread over wider angles.