The Path to N3LO Parton Distribution Functions

• Emanuele Roberto Nocera (University of Turin)

Room: A.1.01/03 - Alps I present an extension of the NNPDF4.0 parton distribution functions (PDFs) at approximate next-to-next-to-next-to-leading order (N3LO). In particular, I discuss how an approximation for the N3LO splitting functions can be constructed from available fixed-order and resummed computations, and how this can be combined with (partial) knowledge of N3LO partonic matrix elements to determine a set of N3LO PDFs. I explain how this set incorporates uncertainties from incomplete knowledge of N3LO terms in the splitting functions, and from missing higher-order corrections, estimated by scale variation, through a theory covariance matrix formalism. I assess the perturbative stability of the PDFs, compare them with those from MSHT, and examine the phenomenological impact of approximate N3LO corrections on parton luminosities at the LHC, and on the Higgs and Drell-Yan total production cross sections.