A measurement of the production cross section for two isolated photons in proton-proton collisions at a
center-of-mass energy of ffiffi
s p ¼ 8 TeV is presented. The results are based on an integrated luminosity of
20.2 fb−1 recorded by the ATLAS detector at the Large Hadron Collider. The measurement considers
photons with pseudorapidities satisfying jηγ j < 1.37 or 1.56 < jηγ j < 2.37 and transverse energies of
respectively Eγ
T;1 > 40 GeV and Eγ
T;2 > 30 GeV for the two leading photons ordered in transverse energy
produced in the interaction. The background due to hadronic jets and electrons is subtracted using datadriven
techniques. The fiducial cross sections are corrected for detector effects and measured differentially
as a function of six kinematic observables. The measured cross section integrated within the fiducial
volume is 16.8  0.8 pb. The data are compared to fixed-order QCD calculations at next-to-leading-order
and next-to-next-to-leading-order accuracy as well as next-to-leading-order computations including
resummation of initial-state gluon radiation at next-to-next-to-leading logarithm or matched to a parton
shower, with relative uncertainties varying from 5% to 20%.

Title

Physical Review D

Publisher

American Physical Society

Publisher Country

United States of America

Indexing

Thomson Reuters

Impact Factor

147.302

Publication Type

Prtinted only

Volume

95

Year

2017

Pages

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