Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

TL;DR

This paper reports a measurement of the inclusive isolated prompt photon production cross-section in proton-proton collisions at 7 TeV using ATLAS data, comparing results with QCD predictions.

Contribution

First measurement of the differential cross-section for isolated prompt photons at 7 TeV with detailed data-driven background estimation.

Findings

Results agree with NLO QCD calculations within uncertainties.

Cross-section measured over a wide energy range from 45 to 400 GeV.

Data covers two pseudorapidity regions, enhancing spatial understanding.

Abstract

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.