Extracting jet transport coefficient from jet quenching at RHIC and LHC
Within ﬁve diﬀerent approaches to parton propagation and energy loss in dense matter, a phenomenological study of experimental data on suppression of large p T single inclusive hadrons in heavy-ion collisions at both RHIC and LHC was carried out. The evolution of bulk medium used in the study for parton propagation was given by 2+1D or 3+1D hydrodynamic models which are also constrained by experimental data on bulk hadron spectra. Values for the jet transport parameter ˆ q at the center of the most central heavy-ion collisions are extracted or calculated within each model, with parameters for the medium properties that are constrained by experimental data on the hadron suppression factor R AA . For a quark with initial energy of 10 GeV we ﬁnd that ˆ q ≈ 1 . 2 ± 0 . 3 GeV 2 /fm at an initial time τ 0 = 0 . 6 fm/ c in Au+Au collisions at √ s = 200 GeV/n and ˆ q ≈ 1 . 9 ± 0 . 7 GeV 2 /fm in Pb+Pb collisions at √ s = 2 . 76 TeV/n. Compared to earlier studies, these represent signiﬁcant convergence on values of the extracted jet transport parameter, reﬂecting recent advances in theory and the availability of new experiment data from the LHC.