Production of muons from heavy-flavour hadron decays at high transverse momentum in Pb-Pb collisions at ,root S-NN=5.02 and 2.76 TeV

Measurements of the production of muons from heavy-flavour hadron decays in Pb-Pb collisions at root s(NN) = 5.02 and 2.76 TeV using the ALICE detector at the LHC are reported. The nuclear modification factor R-AA at root s(NN) = 5.02 TeV is measured at forward rapidity (2.5 < y < 4) as a function of transverse momentum p(T) in central, semi-central, and peripheral collisions over a wide p(T) interval, 3 < p(T) < 20 GeV/c, in which muons from beauty-hadron decays are expected to take over from charm as the dominant source at high p(T) (p(T) > 7 GeV/c). The R-AA shows an increase of the suppression of the yields of muons from heavy-flavour hadron decays with increasing centrality. A suppression by a factor of about three is observed in the 10% most central collisions. The R-AA at root s(NN) = 5.02 TeV is similar to that at root s(NN) = 2.76 TeV. The precise R-AA measurements have the potential to distinguish between model predictions implementing different mechanisms of parton energy loss in the high-density medium formed in heavy-ion collisions. They place important constraints for the understanding of the heavy-quark interaction with the hot and dense QCD medium.