Direct photon production and PDF fits reloaded
Direct photon production in hadronic collisions provides a handle on the gluon PDF by means of the QCD Compton scattering process. In this work we revisit the impact of direct photon production on a global PDF analysis, motivated by the recent availability of the next-to-next-to-leading (NNLO) calculation for this process. We demonstrate that the inclusion of NNLO QCD and leading-logarithmic electroweak corrections leads to a good quantitative agreement with the ATLAS measurements at 8 and 13 TeV, except for the most forward rapidity region in the former case. By including the ATLAS 8 TeV direct photon production data in the NNPDF3.1 NNLO global analysis, we assess its impact on the medium-x gluon. We also study the constraining power of the direct photon production measurements on PDF fits based on different datasets, in particular on the NNPDF3.1 no-LHC and collider-only fits. Here, we also present updated NNLO theoretical predictions for direct photon production at 13 TeV that include the constraints from the 8 TeV measurements.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1441089
- Alternate ID(s):
- OSTI ID: 1422193
- Report Number(s):
- FERMILAB-PUB-18-018-T; Nikhef/2017-068; OUTP-17-16P; NIKHEF-2017-068; arXiv:1802.03021; 470; PII: 5944
- Journal Information:
- European Physical Journal. C, Particles and Fields, Journal Name: European Physical Journal. C, Particles and Fields Vol. 78 Journal Issue: 6; ISSN 1434-6044
- Publisher:
- Springer Science + Business MediaCopyright Statement
- Country of Publication:
- Germany
- Language:
- English
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