Elliptic Flow of Muons from Heavy-Flavour Hadron Decays at Forward Rapidity in Pb–Pb Collisions at √sNN = 2.76 TeV

Abstract

The elliptic flow, v₂, of muons from heavy-flavour hadron decays at forward rapidity (2.5 < y < 4) is measured in Pb–Pb collisions at √sNN = 2.76 TeV with the ALICE detector at the LHC. The scalar product, two- and four-particle Q cumulants and Lee–Yang zeros methods are used. The dependence of the v₂ of muons from heavy-flavour hadron decays on the collision centrality, in the range 0–40%, and on transverse momentum, p[subscript T], is studied in the interval 3 < p[subscript T] < 10GeV/c. A positive is observed with the scalar product and two-particle Q cumulants in semi-central collisions (10–20% and 20–40% centrality classes) for the p[subscript T] interval from 3 to about 5 GeV/c with a significance larger than 3σ, based on the combination of statistical and systematic uncertainties. The v₂ magnitude tends to decrease towards more central collisions and with increasing p[subscript T]. It becomes compatible with zero in the interval 6 < p[subscript T] < 10GeV/c. The results are compared to models describing the interaction of heavy quarks and open heavy-flavour hadrons with the high-density medium formed in high-energy heavy-ion collisions. Keywords: LHC; ALICE experiment; Pb–Pb collisions; Heavy-flavour decay muons; Elliptic flow