Measurement of the suppression and vn of heavy flavor muons in lead-lead collisions with the ATLAS detector

ATLAS has measured the production of heavy flavor muons in 2.76 TeV pp and Pb+Pb collisions at the LHC. The measurements are performed over the transverse momentum range 4 < pT < 14 GeV and for five Pb+Pb centrality intervals. Backgrounds arising from in-flight pion and kaon decays, hadronic showers, and mis-reconstructed muons are statistically removed using a template fitting procedure. The heavy flavor muon differential cross-sections and per-event yields are measured in pp and Pb+Pb collisions, respectively. The nuclear modification factor, RAA , is observed to be independent of pT within uncertainties and to be less than unity, which indicates suppressed production of heavy flavor muons in Pb+Pb collisions. The heavy flavor muon yield is measured as a function of the azimuthal angle difference, phi-Psi_{2}, where the experimental event plane angle, Psi_{2} is measured in forward calorimeters that cover 3.2 < |y| < 4.9. Fourier coefficients associated with the cos(2(phi-Psi_{2})) modulation, v2 , are measured as a function of pT and centrality. They vary slowly with pT and show a systematic variation with centrality that is characteristic of other elliptic anisotropy measurements. Higher harmonics v3 and v4 are also measured using Scalar Product method.