Abstract
ATLAS measurements of the production of muons from heavy-flavor decays in √𝑠𝑁𝑁=2.76 TeV Pb+Pb collisions and √𝑠=2.76 TeV 𝑝𝑝 collisions at the LHC are presented. Integrated luminosities of 0.14 nb−1 and 570 nb−1 are used for the Pb+Pb and 𝑝𝑝 measurements, respectively, which are performed over the muon 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 misreconstructed 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 obtained from these 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. For the 10% most central Pb+Pb events, the measured 𝑅𝐴𝐴 is approximately 0.35. The azimuthal modulation of the heavy-flavor muon yields is also measured and the associated Fourier coefficients 𝑣𝑛 for 𝑛=2, 3, and 4 are given as a function of 𝑝𝑇 and centrality. They vary slowly with 𝑝𝑇 and show a systematic variation with centrality which is characteristic of other anisotropy measurements, such as that observed for inclusive hadrons. The measured 𝑅𝐴𝐴 and 𝑣𝑛 values are also compared with theoretical calculations.