Measurement of prompt D-s(+)-meson production and azimuthal anisotropy in Pb-Pb collisions at root s(NN)=5.02 TeV

The production yield and angular anisotropy of prompt D-s(+) mesons were measured as a function of transverse momentum (p(T)) in Pb-Pb collisions at a centre-of-mass energy per nucleon pair root s(NN) = 5.02 TeV collected with the ALICE detector at the LHC. D-s(+) mesons and their charge conjugates were reconstructed at midrapidity (vertical bar y vertical bar < 0.5) from their hadronic decay channel D-s(+) -> phi pi(+), with phi -> K-K+, in the p(T) intervals 2 < p(T) < 50 GeV/c and 2 < p(T) < 36 GeV/c for the 0-10% and 30-50% centrality intervals. For p(T) > 10 GeV/c, the measured D-s(+)-meson nuclear modification factor R-AA is consistent with the one of non-strange D mesons within uncertainties, while at lower p(T) a hint for a D-s(+)-meson R-AA larger than that of non-strange D mesons is seen. The enhanced production of D-s(+) relative to non-strange D mesons is also studied by comparing the p(T)-dependent D-s(+)/D-0 production yield ratios in Pb-Pb and in pp collisions. The ratio measured in Pb-Pb collisions is found to be on average higher than that in pp collisions in the interval 2 < p(T) < 8 GeV/c with a significance of 2.3 sigma and 2.4 sigma for the 0-10% and 30-50% centrality intervals. The azimuthal anisotropy coefficient v(2) of prompt D-s(+) mesons was measured in Pb-Pb collisions in the 30-50% centrality interval and is found to be compatible with that of non-strange D mesons. The main features of the measured R-AA, D-s(+)/D-0 ratio, and v(2) as a function of p(T) are described by theoretical calculations of charm-quark transport in a hydrodynamically expanding quark-gluon plasma including hadronisation via charm-quark recombination with light quarks from the medium. The p(T)-integrated production yield of D-s(+) mesons is compatible with the prediction of the statistical hadronisation model. (c) 2022 European Organization for Nuclear Research, ALICE. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).

Automated summary

The production yield and angular anisotropy of prompt D-s(+) mesons were measured in Pb-Pb collisions at the LHC. It was found that the nuclear modification factor (R-AA) of D-s(+) mesons shows a hint of being larger than that of non-strange D mesons at low transverse momentum (p(T)), while at high p(T), R-AA is consistent with non-strange D mesons. The enhanced production of D-s(+) mesons compared to non-strange D mesons was observed. The azimuthal anisotropy coefficient v(2) of prompt D-s(+) mesons was measured and found to be compatible with that of non-strange D mesons.