Abstract

Measurements of inclusive isolated-photon and photon+jet production in proton–proton collisions at sqrt{s} = 13,text {TeV} are presented. The analysis uses data collected by the CMS experiment in 2015, corresponding to an integrated luminosity of 2.26,text {fb}^{-1}. The cross section for inclusive isolated photon production is measured as a function of the photon transverse energy in a fiducial region. The cross section for photon+jet production is measured as a function of the photon transverse energy in the same fiducial region with identical photon requirements and with the highest transverse momentum jet. All measurements are in agreement with predictions from next-to-leading-order perturbative QCD.

Highlights

  • The measurement of inclusive isolated-photon and photon+jet production cross sections can directly probe quantum chromodynamics (QCD)

  • The differential cross sections for inclusive isolated-photon and photon+jet production in proton-proton collisions at a center-of-mass energy of 13 TeV are measured with a data sample collected by the CMS experiment corresponding to an integrated luminosity of 2.26 fb−1

  • The measurements of inclusive isolated-photon production cross sections are presented as functions of photon transverse energy and rapidity with ETγ > 190 GeV and |yγ | < 2.5

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Summary

Introduction

The measurement of inclusive isolated-photon and photon+jet production cross sections can directly probe quantum chromodynamics (QCD). The dominant production processes in proton–proton (pp) collisions at the energies of the CERN LHC are quark–gluon Compton scattering qg → qγ , together with contributions from quark-antiquark annihilation qq → gγ , and parton fragmentation qq(gg) → X + γ Both the CMS and ATLAS Collaborations have reported measurements of the differential cross sections for isolated prompt photon production [1,2,3,4,5,6,7] and for the production of a photon in association with jets [8,9,10] using data with centerof-mass energies of 2.76, 7, and 8 TeV. Photon yields are extracted using the shape of the BDT distributions, and the measured cross sections are compared to the results of NLO QCD calculations

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Simulation samples
Data samples and event selection criteria
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Background
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Systematic uncertainties
Results and comparison with theory
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Summary
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Findings
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Full Text
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