Measurement of the inclusive isolated prompt photon cross section in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper reports a measurement of the inclusive isolated prompt photon production cross section in proton-proton collisions at 7 TeV using the ATLAS detector, covering specific pseudorapidity and energy ranges.

Contribution

It provides the first detailed measurement of isolated prompt photon cross sections at 7 TeV with the ATLAS detector, comparing results to NLO QCD predictions.

Findings

Measured cross sections agree with NLO QCD within uncertainties

Photon identification combines calorimeter and tracker data

Background estimated from data using isolation energy distribution

Abstract

A measurement of the cross section for the inclusive production of isolated prompt photons in pp collisions at a centre-of-mass energy sqrt(s) = 7TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<|eta|<1.81 in the transverse energy range 15 < E_T <100 GeV. The results are based on an integrated luminosity of 880 nb-1, collected with the ATLAS detector at the Large Hadron Collider. Photon candidates are identified by combining information from the calorimeters and from the inner tracker. Residual background in the selected sample is estimated from data based on the observed distribution of the transverse isolation energy in a narrow cone around the photon candidate. The results are compared to predictions from next-to-leading order perturbative QCD calculations.