Parton distributions based on a maximally consistent dataset

Abstract

The choice of data that enters a global QCD analysis can have a substantial impact on the resulting parton distributions and their predictions for collider observables. One of the main reasons for this has to do with the possible presence of inconsistencies, either internal within an experiment or external between different experiments. In order to assess the robustness of the global fit, different definitions of a conservative PDF set, that is, a PDF set based on a maximally consistent dataset, have been introduced. However, these approaches are typically affected by theory biases in the selection of the dataset. In this contribution, after a brief overview of recent NNPDF developments, we propose a new, fully objective, definition of a conservative PDF set, based on the Bayesian reweighting approach. Using the new NNPDF3.0 framework, we produce various conservative sets, which turn out to be mutually in agreement within the respective PDF uncertainties, as well as with the global fit. We explore some of their implications for LHC phenomenology, finding also good consistency with the global fit result. These results provide a non-trivial validation test of the new NNPDF3.0 fitting methodology, and indicate that possible inconsistencies in the fitted dataset do not affect substantially the global fit PDFs.

6 pages, 3 figures, to appear in the proceedings of the 37th International Conference of High-Energy Physics (ICHEP2014), 2-9 July 2014, Valencia, Spain

References in corpus (7)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Squark and gluino production cross sections in pp collisions at $\sqrt{s}$ = 13, 14, 33 and 100 TeV
• Evidence for polarization of gluons in the proton
• Second order QCD corrections to jet production at hadron colliders: the all-gluon contribution
• aMCfast: automation of fast NLO computations for PDF fits
• Perturbative QCD description of jet data from LHC Run-I and Tevatron Run-II
• Unbiased determination of polarized parton distributions and their uncertainties