Measurement of the production cross section of √ three isolated photons in p p collisions at s = 8 TeV using the ATLAS detector

F. MONTICELLI,ATLAS COLLABORATION

PHYSICS LETTERS B

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018

0370-2693

A measurement of the production of three isolated photons in proton?proton collisions at√a centre-of-mass energy s = 8 TeV is reported. The results are based on an integratedluminosity of 20.2 fb −1 collected with the ATLAS detector at the LHC. The differential crosssections are measured as functions of the transverse energy of each photon, the differencein azimuthal angle and in pseudorapidity between pairs of photons, the invariant mass ofpairs of photons, and the invariant mass of the triphoton system. A measurement of theinclusive fiducial cross section is also reported. Next-to-leading-order perturbative QCDpredictions are compared to the cross-section measurements. The predictions underestimatethe measurement of the inclusive fiducial cross section and the differential measurements atlow photon transverse energies and invariant masses. They provide adequate descriptions ofthe measurements at high values of the photon transverse energies, invariant mass of pairs ofphotons, and invariant mass of the triphoton system.