Doped Parton Distributions

TL;DR

This paper introduces the doped scheme for parton distribution functions, blending features of 4-flavour and 5-flavour schemes, and presents NNPDF3.0 sets to improve high-energy b-quark process calculations at the LHC.

Contribution

It provides the first NNPDF3.0 PDF sets in the doped scheme, comparing them with existing schemes and discussing their phenomenological implications.

Findings

Doped scheme offers a hybrid approach for b-quark processes.

NNPDF3.0 doped PDFs differ from 4FS and 5FS sets.

Relevance for LHC phenomenology is discussed.

Abstract

Calculations of high-energy processes involving the production of b-quarks are typically performed in two different ways, the massive four-flavour scheme (4FS) and the massless five-flavour scheme (5FS). For processes where the combination of the 4FS and 5FS results into a matched calculation is technically difficult, it is possible to define a hybrid scheme known as the doped scheme, where above the b-quark threshold the strong coupling runs with $n_f=5$, as in the massless calculation, while the DGLAP splitting functions are those of the $n_f=4$ scheme. In this contribution we present NNPDF3.0 PDF sets in this doped scheme, compare them with the corresponding 4FS and 5FS sets, and discuss their relevance for LHC phenomenology.