Centrality dependence of high-$p_{\rm T}$ D meson suppression in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

TL;DR

This paper measures the suppression of prompt D mesons in Pb-Pb collisions at 2.76 TeV, revealing significant centrality-dependent suppression comparable to charged pions, with hints of larger suppression than non-prompt J/psi from B decays.

Contribution

First measurement of D meson nuclear modification factor across multiple centrality classes at LHC energy, providing new insights into charm quark energy loss in quark-gluon plasma.

Findings

Maximum suppression factor of 5-6 in most central collisions

Suppression pattern similar to charged pions within uncertainties

Hints of larger suppression for D mesons compared to non-prompt J/psi

Abstract

The nuclear modification factor, $R_{\rm AA}$, of the prompt charmed mesons ${\rm D^0}$, ${\rm D^+}$ and ${\rm D^{*+}}$, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at a centre-of-mass energy $\sqrt{s_{\rm NN}} = 2.76$ TeV in two transverse momentum intervals, $5<p_{\rm T}<8$ GeV/$c$ and $8<p_{\rm T}<16$ GeV/$c$, and in six collision centrality classes. The $R_{\rm AA}$ shows a maximum suppression of a factor of 5-6 in the 10% most central collisions. The suppression and its centrality dependence are compatible within uncertainties with those of charged pions. A comparison with the $R_{\rm AA}$ of non-prompt ${\rm J}/\psi$ from B meson decays, measured by the CMS Collaboration, hints at a larger suppression of D mesons in the most central collisions.