Prompt D$^{0}$, D$^{+}$, and D$^{*+}$ production in Pb–Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

The collaboration
JHEP 01 (2022) 174, 2022.

Abstract (data abstract)
CERN LHC. The production of prompt D$^{0}$, D$^{+}$, and D*$^{+}$ mesons was measured at midrapidity ($|y|<0.5$) in Pb-Pb collisions at the centre-of-mass energy per nucleon--nucleon pair $\sqrt{s_\mathrm{NN}}=5.02$ TeV with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decay channels and their production yields were measured in central (0-10%) and semicentral (30-50%) collisions. The measurement was performed up to a transverse momentum ($p_\mathrm{T}$) of 36 or 50 GeV/$c$ depending on the D meson species and the centrality interval. For the first time in Pb-Pb collisions at the LHC, the yield of D$^{0}$ mesons was measured down to $p_\mathrm{T} =$ 0, which allowed a model-independent determination of the $p_\mathrm{T}$-integrated yield per unit of rapidity (d$N$/d$y$). A maximum suppression by a factor 5 and 2.5 was observed with the nuclear modification factor ($R_{\mathrm{AA}}$) of prompt D mesons at $p_\mathrm{T} =$ 6-8 GeV/$c$ for the 0-10% and 30-50% centrality classes, respectively. The D-meson $R_{\mathrm{AA}}$ is compared with that of charged pions, charged hadrons, and J/$\psi$ mesons as well as with theoretical predictions. The analysis of the agreement between the measured $R_{\mathrm{AA}}$, elliptic ($v_{2}$) and triangular ($v_{3}$) flow, and the model predictions allowed us to constrain the charm spatial diffusion coefficient $D_{s}$. Furthermore the comparison of $R_{\mathrm{AA}}$ and $v_{2}$ with different implementations of the same models provides an important insight into the role of radiative energy loss as well as charm quark recombination in the hadronisation mechanisms.