Energy Loss in Perturbative QCD

Abstract

We review the properties of energetic parton propagation in hot or cold QCD matter, as obtained in recent works. Advances in understanding the energy loss -collisional and radiative -are summarized, with emphasis on the latter: it features very interesting properties which may help to detect the quark-gluon plasma produced in heavy ion collisions. We describe * preprint BI-TP 2000/08, LPT-Orsay 00-22 submitted to Annual Review of Nuclear and Particle Science two different theoretical approaches, which lead to the same radiated gluon energy spectrum.

Drag force in a string model dual to large-NQCD

“…We shall be concerned mainly with one measured quantity, the energy lost of a highenergy parton in the QGP [7]. We look at two different systems: a single heavy-quark and a di-quark passing through the QGP.…”

Particle production in field theories coupled to strong external sources, I: Formalism and main results

“…Gluon production [29,30,31,32,33,34] and quark pair production [36,37] have been computed numerically previously to leading order in the coupling and to all orders in the source density. There are strong hints that a deeper understanding of thermalization requires an analysis incorporating energy loss effects [61,62,63]. These may include the scattering contributions of the bottom-up scenario [64,65], or equivalently the energy loss induced by collective effects [66,67,68].…”

“…(67) is equivalent to calculating the tree level propagator G +− attached to an arbitrary number of tree diagrams of the type depicted in eq. (62). Each of these attachments, thanks to eq.…”

Charm quenching in heavy-ion collisions at the LHC

“…We calculate in-medium parton energy loss in the framework of the 'BDMPS' (BaierDokshitzer-Mueller-Peigné-Schiff) formalism, reviewed in [3].…”

“…The transport coefficient is defined as the average medium-induced transverse momentum squared transferred to the parton per unit path length,q = k 2 t medium /λ [3]. In the case of a static medium, the distribution of the energy ω of the radiated gluons (for ω ≪ ω c ) is of the form:…”