Charm in the Nucleon

TL;DR

This paper presents a detailed NLO analysis of charm production in nucleons, incorporating mass effects and potential intrinsic charm, finding no strong evidence for intrinsic charm but highlighting areas for future experimental verification.

Contribution

It introduces an interpolating scheme that smoothly connects massless QCD and photon-gluon fusion, including quark mass effects and intrinsic charm considerations.

Findings

No conclusive evidence for intrinsic charm in the nucleon.

Some data points deviate from perturbative QCD predictions.

Future experiments are needed to verify these discrepancies.

Abstract

A next-to-leading order analysis of inelastic electroproduction of charm is performed using an interpolating scheme which maps smoothly onto massless QCD evolution at large Q^2 and photon-gluon fusion at small Q^2. In contrast with earlier analyses, this scheme allows the inclusion of quark and target mass effects and heavy quark thresholds, as well as possible non-perturbative, or intrinsic, charm contributions. We find no conclusive evidence in favor of an intrinsic charm component in the nucleon, although several data points which disagree with perturbative QCD expectations will need to be checked by future experiments.