Impact of Heavy Quark Masses on Parton Distributions and LHC Phenomenology

TL;DR

This paper presents a comprehensive determination of nucleon parton distributions incorporating heavy quark mass effects, assessing their impact on LHC phenomenology and providing uncertainty estimates related to quark mass variations.

Contribution

It introduces a new global PDF set, NNPDF2.1, including heavy quark mass effects using the FONLL-A scheme and evaluates the impact of mass uncertainties on collider observables.

Findings

Heavy quark mass effects significantly influence parton distributions.

Uncertainties in charm and bottom masses affect LHC predictions.

The FONLL-A scheme accurately benchmarks heavy quark treatments.

Abstract

We present a determination of the parton distributions of the nucleon from a global set of hard scattering data using the NNPDF methodology including heavy quark mass effects: NNPDF2.1. In comparison to the previous NNPDF2.0 parton determination, the dataset is enlarged to include deep--inelastic charm structure function data. We implement the FONLL-A general-mass scheme in the FastKernel framework and assess its accuracy by comparison to the Les Houches heavy quark benchmarks. We discuss the impact on parton distributions of the treatment of the heavy quark masses, and we provide a determination of the uncertainty in the parton distributions due to uncertainty in the masses. We assess the impact of these uncertainties on LHC observables by providing parton sets with different values of the charm and bottom quark masses. Finally, we construct and discuss parton sets with a fixed number of flavours.