Azimuthal anisotropies of charged particles with high transverse momentum in Pb+Pb collisions at √𝑠_𝑁⁢𝑁=5.02 TeV with the ATLAS detector

A measurement is presented of elliptic (v₂) and triangular (v₃) azimuthal anisotropy coefficients for charged particles produced in Pb+Pb collisions at √𝑠_𝑁⁢𝑁 = 5.02 TeV using a dataset corresponding to an integrated luminosity of 0.44 nb^-1 collected with the ATLAS detector at the LHC in 2018. The values of v₂ and v₃ are measured for charged particles over a wide range of transverse momentum (p_T), 1-400 GeV, and Pb+Pb collision centrality, 0-60%, using the scalar product and multi-particle cumulant methods. These methods are sensitive to event-by-event fluctuations and non-flow effects in the measurements of azimuthal anisotropies. Positive values of v₂ are observed up to a p_T of approximately 100 GeV from both methods across all centrality intervals. Positive values of v₃ are observed up to approximately 25 GeV using both methods, though the application of the three-subevent technique to the multi-particle cumulant method leads to significant changes at the highest p_T. At high p_T (p_T ⪆ 10 GeV), charged particles are dominantly from jet fragmentation. These jets, and hence the measurements presented here, are sensitive to the path-length dependence of parton energy loss in the quark-gluon plasma produced in Pb+Pb collisions.