Direct photon elliptic flow in Pb–Pb collisions √sNN = 2.76 TeV
ALICE Collaboration. (2019). Direct photon elliptic flow in Pb–Pb collisions √sNN = 2.76 TeV. Physics Letters B, 789, 308-322. doi:10.1016/j.physletb.2018.11.039
Published inPhysics Letters B
Rak, Jan |
© 2018 The Author.
The elliptic flow of inclusive and direct photons was measured at mid-rapidity in two centrality classes 0–20% and 20–40% in Pb–Pb collisions at √sNN = 2.76 TeV by ALICE. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the detector material with the e+e− pairs reconstructed in the central tracking system. The results of the two methods were combined and the direct-photon elliptic flow was extracted in the transverse momentum range 0.9 < pT < 6.2 GeV/c. A comparison to RHIC data shows a similar magnitude of the measured directphoton elliptic flow. Hydrodynamic and transport model calculations are systematically lower than the data, but are found to be compatible.