Speaker
Description
A measurement of
the production cross section for two isolated photons in proton-proton collisions at a
centre-of-mass energy of √ s = 8 TeV is presented. The results are based on an integrated luminosity of 20.24 fb−1
recorded by the ATLAS detector at the Large Hadron Collider. The measurement considers photons with
pseudorapidities satisfying |η γ | < 1.37 or 1.56 < |η γ | < 2.37 and transverse energies of respectively Eγ T,1 > 40
GeV and Eγ T,2 > 30 GeV for the highest and second highest Eγ T photon produced in the interaction. The
background due to hadronic jets and electrons is subtracted using data-driven techniques. The fiducial cross
sections are corrected for detector effects and measured differentially as a function of six kinematic observables. The
data are compared to fixed-order QCD calculations at 16 next-to-leading order (NLO) and
next-to-next-to-leading-order (NNLO) accuracy as well as NLO computations including resummation of initial-state
gluon radiation at next-to-next-to-leading-logarithm or matched to a parton shower.
