May 13 – 19, 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

Measurement of heavy flavor production and azimuthal anisotropy in small and large systems with ATLAS

May 16, 2018, 3:00 PM
Sala Mosaici-2, 3rd Floor (Palazzo del Casinò)

Sala Mosaici-2, 3rd Floor

Palazzo del Casinò

Parallel Talk Open heavy flavour Open heavy flavour


Qipeng Hu (University of Colorado Boulder)


Measurements of heavy flavor hadron production and their correlations in A+A collisions provide insight into the energy loss mechanism and transport properties of heavy quarks in the QGP. From this perspective, the same measurements in $p$+A collisions thus serve as a necessary baseline for understanding the observations in A+A collisions. Additionally, detailed studies of the azimuthal anisotropy for heavy flavor hadrons in $p$+A may help address the question of whether the observed long-range ``ridge'' correlation arises from hard or semi-hard processes, or if it is the result of mechanisms unrelated to the initial hardness scale. This talk presents ATLAS measurements of heavy flavor production, via their semi-leptonic decay to muons in $\sqrt{s_\mathrm{NN}} = 2.76$ TeV Pb+Pb and $pp$ collisions, and via identified prompt $D$ mesons in $\sqrt{s_\mathrm{NN}} = 8.16$ TeV $p$+Pb collisions. Heavy flavor muon yields are observed to be strongly suppressed in Pb+Pb collisions compared to that in $pp$ collisions. On the other hand, the prompt $D$ meson production in $p$+Pb collisions shows no obvious modification compared to the theoretical predictions for $pp$ collisions, indicating relatively small cold nuclear matter effects for $D$ meson production. The $p_{\mathrm{T}}$ and centrality dependence of flow harmonics $v_2$--$v_4$ associated with heavy-flavor muons in Pb+Pb are also presented. The measured $v_2$ decreases over the $p_{\mathrm{T}}$ range of 4--14 GeV, and shows a systematic variation with centrality that was observed in other $v_2$ measurements. The anisotropy measurements are extended to 8.16 TeV $p$+Pb collisions, where the azimuthal modulations of heavy-flavor muons, prompt $D$ mesons and J/$\psi$ are studied using two-particle correlations. The statistical significance of the presence or absence of long range correlations involving heavy flavor production in $p$+Pb events is quantified.

Content type Experiment
Collaboration ATLAS
Centralised submission by Collaboration Presenter name already specified

Primary author

Barbara Krystyna Wosiek (Institute of Nuclear Physics Polish Academy of Sciences (PL))

Presentation materials