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Uncertainties of predictions from parton distributions II: theoretical errors

Martin, A.D.; Roberts, R.G.; Stirling, W.J.; Thorne, R.S.

Authors

A.D. Martin

R.G. Roberts

W.J. Stirling

R.S. Thorne



Abstract

We study the uncertainties in parton distributions, determined in global fits to deep inelastic and related hard scattering data, due to so-called theoretical errors. Amongst these, we include potential errors due to the change of perturbative order (NLO NNLO), and effects, absorptive corrections and higher-twist contributions. We investigate these uncertainties both by including explicit corrections to our standard global analysis and by examining the sensitivity to changes of the x,Q 2,W 2 cuts on the data that are fitted. In this way we expose those kinematic regions where the conventional DGLAP description is inadequate. As a consequence we obtain a set of NLO, and of NNLO, conservative partons where the data are fully consistent with DGLAP evolution, but over a restricted kinematic domain. We also examine the potential effects of such issues as the choice of input parametrisation, heavy target corrections, assumptions about the strange quark sea and isospin violation. Hence we are able to compare the theoretical errors with those uncertainties due to errors on the experimental measurements, which we studied previously. We use W and Higgs boson production at the Tevatron and the LHC as explicit examples of the uncertainties arising from parton distributions. For many observables the theoretical error is dominant, but for the cross section for W production at the Tevatron both the theoretical and experimental uncertainties are small, and hence the NNLO prediction may serve as a valuable luminosity monitor.

Citation

Martin, A., Roberts, R., Stirling, W., & Thorne, R. (2004). Uncertainties of predictions from parton distributions II: theoretical errors. The European Physical Journal C, 35(3), 325-348. https://doi.org/10.1140/epjc/s2004-01825-2

Journal Article Type Article
Publication Date 2004-06
Deposit Date Dec 14, 2006
Journal European Physical Journal C: Particles and Fields
Print ISSN 1434-6044
Electronic ISSN 1434-6052
Publisher SpringerOpen
Peer Reviewed Peer Reviewed
Volume 35
Issue 3
Pages 325-348
DOI https://doi.org/10.1140/epjc/s2004-01825-2
Keywords Inelastic structure functions, Singlet structure functions, Flavor structure functions, To-leading-order, QCD analysis, Higher twist, Anomalous dimension, Small-x, Wilson coefficient, Muon scattering.
Public URL https://durham-repository.worktribe.com/output/1608119