Measurement of the D-meson nuclear modification factor and elliptic flow in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$ with ALICE at the LHC

Abstract

Heavy-flavour hadrons are recognised as a powerful probe for the characterisation of the deconfined medium created in heavy-ion collisions, the Quark-Gluon Plasma (QGP). The ALICE Collaboration measured the production of ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{\ast }$ and ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ mesons in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$. The measurement of the nuclear modification factor ($R_{\mathrm{AA}}$) provides a strong evidence of the in-medium parton energy loss. The comparison between the ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ and the non-strange D-meson $R_{\mathrm{AA}}$ can help to study the hadronisation mechanism of the charm quark in the QGP. In mid-central collisions, the measurement of the D-meson elliptic flow $v_2$ at low transverse momentum ($p_{\mathrm{T}}$) gives insight into the participation of the charm quark into the collective motion of the system, while at high $p_{\mathrm{T}}$ it constrains the path-length dependence of the energy loss. The ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ $v_2$, measured for the first time at the LHC, is found to be compatible to that of non-strange D mesons and positive with a significance of about $2.6\sigma$. Further evidence of a strong coupling of the charm quark to the light quarks of the underlying medium is suggested by the first application of the Event-Shape Engineering (ESE) technique to D-meson elliptic flow.

4 pages, 2 figures, Proceedings of the 17th International Conference on Strangeness in Quark Matter, Utrecht, Netherlands