Energy loss of charm quarks in the quark-gluon plasma: Collisional vs radiative losses

Abstract

In considering the collisional energy loss rates of heavy quarks from hard light parton interactions, we computed the total energy loss of a charm quark for a static medium. For the energy range E ∼ 5-10 GeV of charm quark, it proved to be almost the same order as that of radiative ones estimated to a first-order opacity expansion. The collisional energy loss becomes much more important for lower energy charm quarks, and this feature could be very interesting for the phenomenology of hadrons spectra. Using such collisional energy loss rates, we estimate the momentum loss distribution employing a Fokker-Planck equation and the total energy loss of a charm quark for an expanding quark-gluon plasma under conditions resembling the energies presently available at the BNL Relativistic Heavy Ion Collider. The fractional collisional energy loss is found to be suppressed by a factor of 5 as compared to the static case and does not depend linearly on the system size. We also investigate the heavy to light hadrons D/π ratio at moderately large (5-10 GeV/c) transverse momenta and comment on its enhancement.

Energy loss of a heavy quark moving through Script N = 4 supersymmetric Yang-Mills plasma

“…This constant determines the momentum current flowing along the string. From the expressions (2.13) for these currents, we see that 12) showing that these two currents are constant along the length of the string.…”

“…Most previous work on the rate of energy loss by a charged particle moving in a plasma is based on perturbative weak-coupling approximations [1][2][3][4][5][6][7][8][9][10][11][12]14], but one would like to understand the dynamics in strongly coupled plasmas. The specific question of the energy loss rate of a moving quark in a strongly coupled non-Abelian plasma is of more than theoretical interest.…”

“…(3.2). 12 This static string configuration describes the expectation value of a fundamental representation Wilson line in thermal N = 4 SYM [47,48]. In the finite temperature field theory, this expectation value gives e −βFq ,…”

“…The energy (3.1) of the static string should be interpreted as the free energy of a static quark sitting in the thermal N = 4 SYM medium. 12 In a small abuse of language, we will refer to this free energy as the static thermal mass,…”

“…Energy dissipation of a heavy quark moving through a hot plasma is both theoretically interesting and experimentally relevant [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. A high energy particle moving through a thermal medium is an example of a non-equilibrium dissipative system.…”