Measurement of non-prompt D0-meson elliptic flow in Pb–Pb collisions at sNN=5.02 TeV

Abstract

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