D meson elliptic flow in non-central Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76TeV

TL;DR

This study measures the elliptic flow of D mesons in non-central Pb-Pb collisions at 2.76 TeV, revealing significant positive flow consistent with light-flavour hadrons, indicating charm quark participation in the medium's collective motion.

Contribution

First measurement of D meson elliptic flow at LHC energies, demonstrating charm quark coupling to the quark-gluon plasma's collective expansion.

Findings

D meson $v_2$ is positive for 2-6 GeV/c $p_T$

D meson flow magnitude is comparable to light-flavour hadrons

Results have 5.7σ significance

Abstract

Azimuthally anisotropic distributions of D$^0$, D$^+$ and D$^{*+}$ mesons were studied in the central rapidity region ($|y|<0.8$) in Pb-Pb collisions at a centre-of-mass energy $\sqrt{s_{\rm NN}} = 2.76$ TeV per nucleon-nucleon collision, with the ALICE detector at the LHC. The second Fourier coefficient $v_2$ (commonly denoted elliptic flow) was measured in the centrality class 30-50% as a function of the D meson transverse momentum $p_{\rm T}$, in the range 2-16 GeV/$c$. The measured $v_2$ of D mesons is comparable in magnitude to that of light-flavour hadrons. It is positive in the range $2 < p_{\rm T} < 6$ GeV/$c$ with $5.7\sigma$ significance, based on the combination of statistical and systematic uncertainties.