A derivation of the source term induced by a fast parton from the quark energy-momentum tensor

Abstract

The distribution of energy and momentum deposited by a fast parton in a medium of thermalized quarks, or the source term, is evaluated in perturbative thermal field theory. The calculation is performed by directly evaluating the thermal expectation value of the quark energy-momentum tensor. The fast parton is coupled to the medium by adding an interaction term to the Lagrangian. I show that this approach is very general and can be modified to consider more realistic modeling of fast parton propagation, such as a fast parton created in an initial hard interaction or the evolution of a parton shower due to medium induced radiation. For the scenario considered here, it is found that local excitations fall sharply as a function of the energy of the fast parton. These local excitations couple directly to the sound mode in hydrodynamics and are important for generating an observable shockwave structure. This may have implications for the trigger pT dependence of measurements of azimuthal dihadron particle correlations in heavy-ion collisions. In particular, one would be less likely to observe a conical emission pattern for increasing trigger pT.

7 pages and 3 figures. Contribution to the proceedings of the 27th Winter Workshop on Nuclear Dynamics held in Winter Park, Colorado

References in corpus (14)

• Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at sqrt(S(NN))= 2.76 TeV with the ATLAS Detector at the LHC
• Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV
• Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Suppression of elliptic flow in a minimally viscous quark-gluon plasma
• Explanation of Di-jet asymmetry in Pb+Pb collisions at the Large Hadron Collider
• Energy and momentum deposited into a QCD medium by a jet shower
• Sonic Mach Cones Induced by Fast Partons in a Perturbative Quark-Gluon Plasma
• The physics of $Z^0/{\gamma }^{\ast }$-tagged jets at the LHC
• The sound produced by a fast parton in the quark-gluon plasma is a "crescendo"
• Parton showers as sources of energy-momentum deposition in the QGP and their implication for shockwave formation at RHIC and at the LHC
• Mach cones in the quark-gluon plasma: Viscosity, speed of sound, and effects of finite source structure
• Fast partons as a source of energy and momentum in a perturbative quark-gluon plasma
• Medium-modified Jet Shapes and other Jet Observables from in-medium Parton Shower Evolution
• Thermal field theory derivation of the source term induced by a fast parton from the quark energy-momentum tensor