Speaker
Edmond Iancu
(Institut de Physique Théorique de Saclay)
Description
We discuss average properties of the gluon cascade generated by an energetic parton propagating through a dense QCD medium. The cascade is mostly made with relatively soft gluons, whose production is not suppressed by the LPM effect. Unlike for usual QCD cascades in the vacuum, where the typical splittings are very asymmetric (soft and collinear), the medium-induced branchings are quasi-democratic and lead to wave turbulence. This results in a very efficient mechanism for the transport of energy at large angles with respect to the jet axis, which might explain the di-jet asymmetry observed in Pb-Pb collisions at the LHC. We furthermore present the equations describing the non-linear evolution of the jet quenching parameter with increasing the medium size, to leading logarithmic accuracy in perturbative QCD. These equations may be viewed as a generalization, going beyond the
eikonal approximation, of the BK-JIMWLK equations for the gluon
distribution in a large nucleus. An important prediction of these equations is a rapid growth
of the jet quenching parameter with increasing the medium size L.
Author
Edmond Iancu
(Institut de Physique Théorique de Saclay)
