Parton distributions incorporating QED contributions

By Alan D. Martin, R. G. Roberts, W. Stirling, R. Thorne. 2004

368 citations recorded by the source corpus.

Abstract.We perform a global parton analysis of deep inelastic and related hard-scattering data, including ${{\mathcal{O}}}(\alpha_{\rm QED})$ corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two important physical consequences. First, the different DGLAP evolution of u and d type quarks introduces isospin violation, i.e. $u^p \neq d^n$, which is found to be unambiguously in the direction to reduce the NuTeV $\sin^2\theta_W$ anomaly. A second consequence is the appearance of photon parton distributions $\gamma(x,Q^2)$ of the proton and the neutron. In principle these can be measured at HERA via the deep inelastic scattering processes $e N \to e\gamma X$; our predictions are in agreement with the present data.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/42e9b27d071ae0c0788a291db44451d0e3749bfe

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Citations in the corpus

Electroweak corrections to W + jet hadroproduction including leptonic W-boson decays (2009, methodology): “The O(α)-improved MRSTQED2004 set of PDFs [29] is used throughout implying the value of αs(MZ) stated in (3.”
Top-pair production at the LHC through NNLO QCD and NLO EW (2017, methodology): “We invite the 3The PDF sets MRST2004QED [47] and CT14QED [48] also include QED effects in the DGLAP evolution, but they are not NNLO QCD accurate.”
Search for new high-mass phenomena in the dilepton final state using 36 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 13 TeV with the ATLAS detector (2017, methodology): “Those include photon-induced contributions (γγ → `` via t- and u-channel processes) computed with the MRST2004QED PDF set [31].”
Electroweak corrections to dilepton + jet production at hadron colliders (2011, methodology): “Only the photoninduced processes are evaluated with the MRSTQED2004 set of PDFs [76] as discussed in section 2.”
Measurement of the Z/ѵ* boson transverse momentum distribution in pp collisions at √s = 7 TeV with the ATLAS detector (2014, methodology): “Photon-induced dilepton production, i.e. the double dissociative process q ¯ q → + ` − and inelastic photon-induced pp → + ` − , is simulated using Horace [39] and Herwig++ [40], inter-faced to the MRST2004qed PDFs [41].”
The Structure of the Proton in the LHC Precision Era (2017, background): “Thus, within such approaches the photon PDF is completely predicted within the specific model, up to any freedom in the model parameters, such as the choice of quark masses for MRST2004QED or the overall normalization for CT14QED.”
NLO electroweak automation and precise predictions for W + multijet production at the LHC (2014, methodology): “This requires the introduction of a photon distribution function and the inclusion of QED effects in the DGLAP evolution of the (anti)quark and photon densities [67, 68].”
A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector (2012, background): “The subprocess is then simply QED Compton scattering, eγ → eγ, and the cross sections are obtained by the convolution [122] dσ(eN → eγX) dxγ = γ(x , μ(2)) σ̂(eγ → eγ).”
Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector (2017, methodology): “20 [97], and these include photon-induced contributions (γγ → `` via t- and u-channel processes) computed with the MRST2004QED PDF set [98].”
The photon content of the proton (2017, result): “Previous results on the photon PDF include MRST2004qed [17], NNPDF23 qed [18] and CT14qed inc [19] (all available within LHAPDF [20]) and the HKR16 set [21].”