Measurement of non-prompt D -meson elliptic flow in Pb–Pb collisions at √sNN=5.02 TeV

Abstract

Abstract The elliptic flow $$(v_2)$$ ( v 2 ) of $${\textrm{D}}^{0}$$ D 0 mesons from beauty-hadron decays (non-prompt $${\textrm{D}}^{0})$$ D 0 ) was measured in midcentral (30–50%) Pb–Pb collisions at a centre-of-mass energy per nucleon pair $$\sqrt{s_{\textrm{NN}}} = 5.02$$ s NN = 5.02 TeV with the ALICE detector at the LHC. The $${\textrm{D}}^{0}$$ D 0 mesons were reconstructed at midrapidity $$(|y| ( | y | 0.8 ) from their hadronic decay $$\mathrm {D^0 \rightarrow K^-\uppi ^+}$$ D 0 → K - π + , in the transverse momentum interval $$2 2 p T 12 GeV/ c . The result indicates a positive $$v_2$$ v 2 for non-prompt $${{\textrm{D}}^{0}}$$ D 0 mesons with a significance of 2.7 $$\sigma $$ σ . The non-prompt $${{\textrm{D}}^{0}}$$ D 0 -meson $$v_2$$ v 2 is lower than that of prompt non-strange D mesons with 3.2 $$\sigma $$ σ significance in $$2 2 p T 8 GeV / c , and compatible with the $$v_2$$ v 2 of beauty-decay electrons. Theoretical calculations of beauty-quark transport in a hydrodynamically expanding medium describe the measurement within uncertainties.