Measurement of prompt D$^0$ meson azimuthal anisotropy in PbPb collisions at $\sqrt{s_\mathrm{NN}} = $5.02 TeV

TL;DR

This paper reports the first measurements of prompt D0 meson azimuthal anisotropy coefficients v2 and v3 in PbPb collisions at 5.02 TeV, revealing insights into charm quark interactions with the quark-gluon plasma.

Contribution

It provides the first measurement of the prompt D0 meson v3 coefficient and compares charm quark flow to charged particles, offering new constraints on charm-medium interactions.

Findings

v2 is positive across the studied pT range

First measurement of prompt D0 v3 coefficient, up to 0.07 at 4 GeV/c

Charm quark flow shows collective motion at low pT and path length dependence at high pT

Abstract

The prompt D$^0$ meson azimuthal anisotropy coefficients, $v_2$ and $v_3$, are measured at midrapidity ($|y| < 1.0$) in PbPb collisions at a center-of-mass energy $\sqrt{s_\mathrm{NN}} = $5.02 TeV per nucleon pair with data collected by the CMS experiment. The measurement is performed in the transverse momentum ($p_\mathrm{T}$) range of 1 to 40 GeV/c, for central and midcentral collisions. The $v_2$ coefficient is found to be positive throughout the $p_\mathrm{T}$ range studied. The first measurement of the prompt D$^0$ meson $v_3$ coefficient is performed, and values up to 0.07 are observed for $p_\mathrm{T}$ around 4 GeV/c. Compared to measurements of charged particles, a similar $p_\mathrm{T}$ dependence, but smaller magnitude for $p_\mathrm{T} < $6 GeV/c, is found for prompt D$^0$ meson $v_2$ and $v_3$ coefficients. The results are consistent with the presence of collective motion of charm quarks at low $p_\mathrm{T}$ and a path length dependence of charm quark energy loss at high $p_\mathrm{T}$, thereby providing new constraints on the theoretical description of the interactions between charm quarks and the quark-gluon plasma.