Nuclear modification factor of $D^0$ mesons in PbPb collisions at $\sqrt{^s{NN}}$ = 5.02 TeV

Abstract

The transverse momentum $(p_T)$ spectrum of prompt $D^0$ mesons and their antiparticles has been measured via the hadronic decay channels $D^0\rightarrow K^-\pi^+$ and in and PbPb collisions at a centre-of-mass energy of 5.02 TeV per nucleon pair with the CMS detector at the LHC. The measurement is performed in the $D^0$ meson $p_T$ range of 2–100 GeV/ and in the rapidity range of $\left |y\right |<1 $. The pp (PbPb) dataset used for this analysis corresponds to an integrated luminosity of $27.4 pb^{−1} (530 μb^{−1})$. The measured$D^0$ meson $p_T$ spectrum in pp collisions is well described by perturbative QCD calculations. The nuclear modification factor, comparing $D^0$ meson yields in PbPb and pp collisions, was extracted for both minimum-bias and the 10% most central PbPb interactions. For central events, the $D^0$ meson yield in the PbPb collisions is suppressed by a factor of 5–6 compared to the pp reference in $p_T$ the range of 6–10 GeV/c. For $D^0$ mesons in the high $p_T$ range of 60–100 GeV/c, a significantly smaller suppression is observed. The results are also compared to theoretical calculations.