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 F-2 and F-L 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 F-2 and F-L, 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 formula for the polarised photon PDF, as well as the photon TMDPDF. Using our formula, we derive the P-gamma i subset of DGLAP splitting functions to order alpha alpha(s) and alpha(2), 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

Manohar, A., Nason, P., Salam, G., Zanderighi, G. (2017). The photon content of the proton. JOURNAL OF HIGH ENERGY PHYSICS, 2017(12) [10.1007/JHEP12(2017)046].

The photon content of the proton

Nason, P;Zanderighi, G
2017

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 F-2 and F-L 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 F-2 and F-L, 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 formula for the polarised photon PDF, as well as the photon TMDPDF. Using our formula, we derive the P-gamma i subset of DGLAP splitting functions to order alpha alpha(s) and alpha(2), 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
Articolo in rivista - Articolo scientifico
Deep Inelastic Scattering (Phenomenology); QCD Phenomenology; INELASTIC STRUCTURE FUNCTIONS; PARTON DISTRIBUTION-FUNCTIONS; 3-LOOP; SPLITTING FUNCTIONS; NNLO EVOLUTION; LEADING ORDER; QCD; SCATTERING; DISTRIBUTIONS; SPIN; ELECTROPRODUCTION
English
2017
2017
12
46
open
Manohar, A., Nason, P., Salam, G., Zanderighi, G. (2017). The photon content of the proton. JOURNAL OF HIGH ENERGY PHYSICS, 2017(12) [10.1007/JHEP12(2017)046].
File in questo prodotto:
File Dimensione Formato  
Manohar2017_Article_ThePhotonContentOfTheProton.pdf

accesso aperto

Descrizione: Articolo principale
Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 2.51 MB
Formato Adobe PDF
2.51 MB Adobe PDF Visualizza/Apri
10281-217869.pdf

accesso aperto

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 2.51 MB
Formato Adobe PDF
2.51 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/217869
Citazioni
  • Scopus 172
  • ???jsp.display-item.citation.isi??? 156
Social impact