Nucleon structure in terms of OPE with non-perturbative Wilson coefficients

TL;DR

This paper uses lattice QCD to non-perturbatively evaluate Wilson coefficients in the Operator Product Expansion, enhancing the understanding of nucleon structure functions through improved theoretical calculations.

Contribution

It introduces a non-perturbative method to compute Wilson coefficients using lattice QCD with overlap quarks, reducing operator mixing and lattice artifacts.

Findings

Wilson coefficients computed non-perturbatively

Use of overlap quarks suppresses operator mixing

Results obtained via Singular Value Decomposition

Abstract

Lattice calculations could boost our understanding of Deep Inelastic Scattering by evaluating moments of the Nucleon Structure Functions. To this end we study the product of electromagnetic currents between quark states. The Operator Product Expansion (OPE) decomposes it into matrix elements of local operators (depending on the quark momenta) and Wilson coefficients (as functions of the larger photon momenta). For consistency with the matrix elements, we evaluate a set of Wilson coefficients non-perturbatively, based on propagators for numerous momentum sources, on a 24^3 x 48 lattice. The use of overlap quarks suppresses unwanted operator mixing and lattice artifacts. Results for the leading Wilson coefficients are extracted by means of Singular Value Decomposition.