Journal article
The photon content of the proton
- Abstract:
- The photon PDF of the proton is needed for precision comparisons of LHC cross sections with theoretical predictions. In a recent paper, we showed how the photon PDF could be determined in terms of the electromagnetic proton structure functions F2 and FL measured in electron-proton scattering experiments, and gave an explicit formula for the PDF including all terms up to next-to-leading order. In this paper we give details of the derivation. We obtain the photon PDF using the factorisation theorem and applying it to suitable BSM hard scattering processes. We also obtain the same PDF in a process-independent manner using the usual definition of PDFs in terms of light-cone Fourier transforms of products of operators. We show how our method gives an exact representation for the photon PDF in terms of F2 and FL, valid to all orders in QED and QCD, and including all non-perturbative corrections. This representation is then used to give an explicit formula for the photon PDF to one order higher than our previous result. We also generalise our results to obtain formulæ for the polarised photon PDF, as well as the photon TMDPDF. Using our formula, we derive the Pγi subset of DGLAP splitting functions to order ααs and α2, which agree with known results. We give a detailed explanation of the approach that we follow to determine a photon PDF and its uncertainty within the above framework.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 2.5MB, Terms of use)
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- Publisher copy:
- 10.1007/JHEP12(2017)046
Authors
- Publisher:
- Springer Verlag
- Journal:
- Journal of High Energy Physics More from this journal
- Volume:
- 2017
- Issue:
- 46
- Pages:
- 1-77
- Publication date:
- 2017-12-11
- Acceptance date:
- 2017-11-06
- DOI:
- EISSN:
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1029-8479
- ISSN:
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1126-6708
- Keywords:
- Pubs id:
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pubs:813687
- UUID:
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uuid:495ea34c-a886-40e6-aa09-a8e78d0465ee
- Local pid:
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pubs:813687
- Source identifiers:
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813687
- Deposit date:
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2018-11-30
Terms of use
- Copyright holder:
- Manohar et al
- Copyright date:
- 2017
- Notes:
- © The Author(s) 2017. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
- Licence:
- CC Attribution (CC BY)
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