Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb-Pb collisions at \(\sqrt{s_{\rm NN}}=2.76\) TeV

Abstract

The elliptic flow, \(v_{2}\). of muons from heavy-flavour hadron decays at forward rapidity \(2.5 < y < 4\) is measured in Pb--Pb collisions at \(\sqrt{s_{\rm NN}}\) = 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 \(v_2\) of muons from heavy-flavour hadron decays on the collision centrality, in the range 0--40%, and on transverse momentum, \(p_{\rm T}\). is studied in the interval \(3 < p_{\rm T} < 10\) GeV/\).\). A positive \(v_2\) is observed with the scalar product and two-particle \(Q\) cumulants in semi-central collisions (10--20% and 20--40% centrality classes) for the \(p_{\rm T}\) interval from 3 to about 5 GeV/\).\). The \(v_2\) magnitude tends to decrease towards more central collisions and with increasing \(p_{\rm T}\). It becomes compatible with zero in the interval \(6 < p_{\rm T} < 10{\rm GeV/}c\). 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. The model calculations describe the measured \(v_2\) within uncertainties.