Photon-jet correlations in $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV $pp$ and Pb+Pb collisions with ATLAS at the LHC

Nuclear collisions which produce a high $p_\mathrm{T}$ prompt photon offer a useful way to study the dynamics of the hot, dense medium produced in these events. Being colorless, photons are not influenced by the hot, dense medium. Thus, the outgoing photon serves as a tag of the initial parton flavors, and measures the initial parton $p_\mathrm{T}$ before it is quenched by passage through the medium. In 2015, ATLAS sampled 0.49 nb$^{-1}$ and 26 pb$^{-1}$ of Pb+Pb and $pp$ data at 5.02 TeV, respectively, with a high-level photon trigger that selects $p_\mathrm{T}$>25 GeV photons with high efficiency. The larger prompt photon cross-section and integrated luminosity with respect to 2.76 TeV data allow for new, differential studies of photon-jet correlations. In this talk, ATLAS results on photon-jet azimuthal and pT balance will be presented using photons with $p_\mathrm{T}$ > 60 GeV photons and $R=0.4$, $p_\mathrm{T}$ > 30 GeV jets. Double-differential distributions of the jet-to-photon $p_\mathrm{T}$ ratio, $x_{j\gamma}$, and of the azimuthal difference, $\Delta\phi$, is presented as a function of photon $p_\mathrm{T}$ and event centrality.