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

R. B. Neufeld
2011 Physical Review D  
I derive the distribution of energy and momentum transmitted from a fast parton to a medium of thermalized quarks, or the source term, in perturbative thermal field theory directly from the quark energy-momentum tensor. The fast parton is coupled to the medium by adding an interaction term to the Lagrangian. The thermal expectation value of the energy-momentum tensor source term is then evaluated using standard Feynman rules at finite temperature. It is found that local excitations, which are
more » ... portant for exciting an observable Mach cone structure, fall sharply as a function of the energy of the fast parton. This may have implications for the trigger p_T dependence of measurements of azimuthal dihadron particle correlations in heavy-ion collisions. In particular, a conical emission pattern would be less likely to be observed for increasing trigger p_T. I show that the results presented in this paper can be generalized to more realistic modeling of fast parton propagation, such as through a time dependent interaction term, in future studies.
doi:10.1103/physrevd.83.065012 fatcat:5t3i4sa5kvftpnrptj7rm3kaxa