Finite continuum quasi distributions from lattice QCD

TL;DR

This paper introduces a novel nonperturbative method using gradient flow smearing to extract finite continuum quasi distributions from lattice QCD, enabling direct matching to light-front distributions.

Contribution

It proposes a new approach employing gradient flow to renormalize Wilson-line operators, facilitating continuum limit extraction of quasi distributions from lattice QCD.

Findings

Gradient flow smearing renders matrix elements finite in the continuum limit.

The method allows direct perturbative matching to light-front distributions.

Provides a practical nonperturbative renormalization technique for lattice QCD.

Abstract

We present a new approach to extracting continuum quasi distributions from lattice QCD. Quasi distributions are defined by matrix elements of a Wilson-line operator extended in a spatial direction, evaluated between nucleon states at finite momentum. We propose smearing this extended operator with the gradient flow to render the corresponding matrix elements finite in the continuum limit. This procedure provides a nonperturbative method to remove the power-divergence associated with the Wilson line and the resulting matrix elements can be directly matched to light-front distributions via perturbation theory.