Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=2.76$ TeV

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 $\sqrt{s_{\mathrm{N}\mathrm{N}}}$~=~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, $p_{\mathrm{T}}$, is studied in the interval $3<p_{\mathrm{T}}<10$~GeV/$c$. 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 $p_{\mathrm{T}}$ interval from 3 to about 5 GeV/$c$. The $v_2$ magnitude tends to decrease towards more central collisions and with increasing $p_{\rm T}$\mathrm{.}Itbecomescompatiblewithzerointheinterval$6<p_{\rm T}<10~{\rm GeV/}c$. 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.