Updated Lattice Results for Parton Distributions

TL;DR

This paper presents updated lattice calculations of parton distribution functions, showing improved methods that enable more accurate extraction of PDFs at higher nucleon momenta, aligning well with phenomenological models.

Contribution

The study introduces momentum smearing techniques that significantly enhance lattice computations of PDFs, extending the accessible momentum range and improving the reliability of the results.

Findings

Lattice PDFs resemble phenomenological parameterizations.

Momentum smearing greatly improves matrix element calculations.

Extended nucleon momentum range for more accurate PDFs.

Abstract

We provide an analysis of the x-dependence of the bare unpolarized, helicity and transversity iso-vector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The x-dependence of the calculated PDFs resembles the one of the phenomenological parameterizations, a feature that makes this approach very promising. Furthermore, we apply momentum smearing for the relevant matrix elements to compute the lattice PDFs and find a large improvement factor when compared to conventional Gaussian smearing. This allows us to extend the lattice computation of the distributions to higher values of the nucleon momentum, which is essential for the prospects of a reliable extraction of the PDFs in the future.