Isolated photon and photon+jet production at NNLO QCD accuracy and the ratio $R_{13/8}^\gamma$

We discuss different approaches to photon isolation in fixed-order calculations and present a new next-to-next-to-leading order (NNLO) QCD calculation of $R_{13/8}^\gamma$, the ratio of the inclusive isolated photon cross section at 8 TeV and 13 TeV, differential in the photon transverse momentum, which was recently measured by the ATLAS collaboration.
Comment: 4 pages, 1 figure. Contribution to the 2019 QCD session of the 54th Rencontres de Moriond