Transverse-momentum and event-shape dependence of D-meson flow harmonics in Pb–Pb collisions at s_NN=5.02TeV

The elliptic and triangular flow coefficients v₂ and v₃ of prompt D⁰, D⁺, and D^⁎+ mesons were measured at midrapidity (|y|<0.8) in Pb–Pb collisions at the centre-of-mass energy per nucleon pair of s_NN=5.02TeV with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays in the transverse momentum interval 1<p_T<36GeV/c in central (0–10%) and semi-central (30–50%) collisions. Compared to pions, protons, and J/ψ mesons, the average D-meson v_n harmonics are compatible within uncertainties with a mass hierarchy for p_T≲3GeV/c, and are similar to those of charged pions for higher p_T. The coupling of the charm quark to the light quarks in the underlying medium is further investigated with the application of the event-shape engineering (ESE) technique to the D-meson v₂ and p_T-differential yields. The D-meson v₂ is correlated with average bulk elliptic flow in both central and semi-central collisions. Within the current precision, the ratios of per-event D-meson yields in the ESE-selected and unbiased samples are found to be compatible with unity. All the measurements are found to be reasonably well described by theoretical calculations including the effects of charm-quark transport and the recombination of charm quarks with light quarks in a hydrodynamically expanding medium.