Charm in Deep-Inelastic Scattering

TL;DR

This paper extends the FONLL scheme to include intrinsic charm in deep-inelastic scattering, providing a systematic approach that aligns with existing schemes when intrinsic charm is absent or present, and details the inclusion of heavy quarks up to NNLO.

Contribution

It introduces a systematic extension of the FONLL scheme to account for intrinsic charm in DIS, unifying it with other schemes and including heavy quarks up to NNLO.

Findings

FONLL reduces to S-ACOT without intrinsic charm.

FONLL matches ACOT when intrinsic charm is included.

Explicit NNLO expressions for structure functions are provided.

Abstract

We show how to extend systematically the FONLL scheme for inclusion of heavy quark mass effects in DIS to account for the possible effects of an intrinsic charm component in the nucleon. We show that when there is no intrinsic charm, FONLL is equivalent to S-ACOT to any order in perturbation theory, while when an intrinsic charm component is included FONLL is identical to ACOT, again to all orders in perturbation theory. We discuss in detail the inclusion of top and bottom quarks to construct a variable flavour number scheme, and give explicit expressions for the construction of the structure functions $F^c_2$, $F^c_L$ and $F^c_3$ to NNLO.