Azimuthal anisotropy of dijet events in PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

The path-length dependent parton energy loss within the dense partonic
medium created in lead-lead collisions at a nucleon-nucleon center-of-mass energy of
√sNN = 5.02 TeV is studied by determining the azimuthal anisotropies for dijets with
high transverse momentum. The data were collected by the CMS experiment in 2018
and correspond to an integrated luminosity of 1.69 nb−1
. For events containing back-toback jets, correlations in relative azimuthal angle and pseudorapidity (η) between jets and
hadrons, and between two hadrons, are constructed. The anisotropies are expressed as the
Fourier expansion coefficients vn, n = 2–4 of these azimuthal distributions. The dijet vn
values are extracted from long-range (1.5 < |∆η| < 2.5) components of these correlations,
which suppresses the background contributions from jet fragmentation processes. Positive
dijet v2 values are observed which increase from central to more peripheral events, while
the v3 and v4 values are consistent with zero within experimental uncertainties.