Speaker
Description
The $p_\perp$ dependence of the nuclear modification factor $R_{\rm AA}$ measured in XeXe and PbPb collisions at the LHC exhibits a universal shape, which can be very well reproduced in a simple energy loss model based on the BDMPS medium-induced gluon spectrum. The scaling is observed for various hadron species ($h^\pm$, $D$, $J/\psi$) in different centrality classes and at all colliding energies, $\sqrt{s}=2.76, 5.02, 5.44$ TeV. When comparing different systems, it is found that the average energy loss properly scaled by the particle multiplicity and the transverse area of quark-gluon plasma has a simple dependence on the path length traversed by the fragmenting partons. Based on this model, a data-driven procedure is suggested, which allows for the determination of the first and second moments of the quenching weight without any prior knowledge of the latter.
