Speaker
Description
We extend the existing next-to-next-to-leading (NNLO) NNPDF sets of parton distributions to approximate next-to-next-to-next-to-leading N3LO, as required by the recent availability of an increasing number of computations of scattering processes at this order.
Given the lack of full knowledge of the N3LO splitting functions, we construct an approximation to them which includes all the available partial information from fixed order computations and from resummation. We include known N3LO corrections to deep-inelastic scattering and Drell-Yan production. We account for the partial knowledge of N3LO terms, and for their complete lack of knowledge for some processes, through a theory covariance matrix formalism. We assess the perturbative stability of the resulting PDFs and study their implications for Higgs and gauge boson production at the LHC.
