Quenching of Hadron Spectra in Heavy Ion Collisions at the LHC

The p⊥ dependence of the nuclear modification factor RAA measured in PbPb collisions at the LHC exhibits a universal shape, which can be very well reproduced in a simple energy loss model based on the Baier-Dokshitzer-Mueller-Peigné-Schiff medium-induced gluon spectrum. The scaling is observed for various hadron species (h±, D, J/ψ) in different centrality classes and at both colliding energies, sqrt[s]=2.76 and sqrt[s]=5.02 TeV. Results indicate a 10%-20% increase of the transport coefficient from sqrt[s]=2.76 to sqrt[s]=5.02 TeV, consistent with that of particle multiplicity. 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.