The Compton amplitude and nucleon structure functions

TL;DR

This paper explores a direct method to calculate nucleon structure functions via the Compton amplitude, offering an alternative to traditional approaches and providing insights into proton structure and power corrections.

Contribution

It introduces a Feynman-Hellmann based approach to compute the Compton amplitude directly, bypassing operator mixing and renormalization issues.

Findings

Extracted moments of proton structure functions

Analyzed power corrections to the structure functions

Demonstrated the effectiveness of the Feynman-Hellmann method

Abstract

Structure functions are the essential objects for understanding the deep inelastic scattering processes, providing valuable insight into the partonic structure of hadrons. A direct calculation of the Compton amplitude provides a complementary way to accessing the structure functions, circumventing the operator mixing and renormalisation issues of the standard operator product expansion approach. We describe the connection between the Compton amplitude and the structure functions, and describe a Feynman-Hellmann approach to calculate the amplitude directly. As an application, we extract the moments of transverse and longitudinal proton structure functions and study the power corrections.