The photon content of the proton

Manohar, Aneesh V.; Nason, Paolo; Salam, Gavin P.; Zanderighi, Giulia

doi:10.1007/jhep12(2017)046

Cited by 227 publications

(291 citation statements)

References 68 publications

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“…Concerning the PDFs, we use the LUXqed plus PDF4LHC15 nnlo 100 set [57,58], which is in turn based on the PDF4LHC set [59][60][61][62]. This PDF set includes NLO QED effects in the DGLAP evolution and especially the most precise determination of the photon density.…”

Section: Input Parametersmentioning

confidence: 99%

Large NLO corrections in t t ¯ W ± $$ t\overline{t}{W}^{\pm } $$ and

Frederix

Pagani

Zaro

2018

J. High Energ. Phys.

107

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Abstract:We calculate the complete-NLO predictions for ttW ± and tttt production in proton-proton collisions at 13 and 100 TeV. All the non-vanishing contributions of O(α i s α j ) with i + j = 3, 4 for ttW ± and i + j = 4, 5 for tttt are evaluated without any approximation. For ttW ± we find that, due to the presence of tW → tW scattering, at 13(100) TeV the O(α s α 3 ) contribution is about 12(70)% of the LO, i.e., it is larger than the so-called NLO EW corrections (the O(α 2 s α 2 ) terms) and has opposite sign. In the case of tttt production, large contributions from electroweak tt → tt scattering are already present at LO in the O(α 3 s α) and O(α 2 s α 2 ) terms. For the same reason we find that both NLO terms of O(α 4 s α), i.e., the NLO EW corrections, and O(α 3 s α 2 ) are large (±15% of the LO) and their relative contributions strongly depend on the values of the renormalisation and factorisation scales. However, large accidental cancellations are present (away from the threshold region) between these two contributions. Moreover, the NLO corrections strongly depend on the kinematics and are particularly large at the threshold, where even the relative contribution from O(α 2 s α 3 ) terms amounts to tens of percents.

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Section: Input Parametersmentioning

confidence: 99%

Large NLO corrections in t t ¯ W ± $$ t\overline{t}{W}^{\pm } $$ and

Frederix

Pagani

Zaro

2018

J. High Energ. Phys.

107

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“…Indeed, as discussed in the recent analysis of Ref. [20], it is possible to place quite precise constraints by using low-Q 2 inelastic structure function data. In this work, a dominantly coherent component was also included, and we have seen that the resultant photon PDF lies quite close to our prediction.…”

Section: Discussionmentioning

confidence: 99%

“…In general, as recently discussed in Ref. [20] this incoherent contribution may be constrained from experimental data on F 2 and F L ; however for our considerations it is sufficient to use a simplified model which gives an upper bound on such a contribution. Thus, following Refs.…”

Section: B the Input Distributionmentioning

confidence: 99%

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Photon-initiated processes at high mass

2016

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We consider the influence of photon-initiated processes on high-mass particle production. We discuss in detail the photon parton distribution function (PDF) at relatively high parton x, relevant to such processes, and evaluate its uncertainties. In particular we show that, as the dominant contribution to the input photon distribution is due to coherent photon emission, at phenomenologically relevant scales the photon PDF is already well determined in this region, with the corresponding uncertainties under good control. We then demonstrate the implications of this result for the example processes of high-mass lepton and W boson pair production at the LHC and FCC. While for the former process the photon-initiated contribution is expected to be small, in the latter case we find that it is potentially significant, in particular at larger masses.

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“…Ref. [10] studied the impact of the CMS measurements of W boson pair production at the LHC at 8 TeV on the NNPDF2.3qed, NNPDF3.0qed [11], CT14QEDinc [12], and LUXqed [13] photon PDFs, and found that the data strongly suggest that the NNPDF photon error band should be significantly reduced. Therefore, it is necessary to re-examine the physics effects induced by photon-initiated process.…”

Section: Introductionmentioning

confidence: 99%

Next-to-leading order QCD and electroweak corrections to Higgs-strahlung processes at the LHC

et al. 2018

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In this paper we calculate the total and fiducial cross sections as well as differential distributions for the Higgs-strahlung or VH process pp → VH → lν l /l − l + +H, (V = W or Z, l=e, µ) including QCD and electro-weak corrections up to next-to-leading order before and after reweighting photon PDFs of NNPDF2.3qed, NNPDF3.0qed, MRST2004qed, CT14QEDinc, and LUXqed at the LHC with 13 TeV and Higgs boson mass MH = 125 GeV. The predictions from the various photon PDFs before and after reweighting against each other are in good agreement. The photon PDF uncertainties of the photon-induced cross sections decrease significantly with the reweighting PDFs.

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The photon content of the proton

Cited by 227 publications

References 68 publications

Large NLO corrections in t t ¯ W ± $$ t\overline{t}{W}^{\pm } $$ and

Large NLO corrections in t t ¯ W ± $$ t\overline{t}{W}^{\pm } $$ and

Photon-initiated processes at high mass

Next-to-leading order QCD and electroweak corrections to Higgs-strahlung processes at the LHC

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