Nucleon form factors and moments of parton distributions in twisted mass lattice QCD

TL;DR

This study computes nucleon electroweak form factors and parton distribution moments using twisted mass lattice QCD, analyzing discretization and volume effects across multiple lattice spacings and pion masses.

Contribution

It provides new lattice QCD results on nucleon structure with non-perturbative renormalization and systematic analysis of cut-off and volume effects.

Findings

Results at three lattice spacings show controlled cut-off effects.

Volume dependence is analyzed with two different lattice sizes.

Results are given in the MS scheme at 2 GeV.

Abstract

We present results on the electroweak form factors and on the lower moments of parton distributions of the nucleon, within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Results are obtained on lattices with three different values of the lattice spacings, namely a=0.089 fm, a=0.070 fm and a=0.056 fm, allowing the investigation of cut-off effects. The volume dependence is examined by comparing results on two lattices of spatial length L=2.1 fm and L=2.8 fm. The simulations span pion masses in the range of 260-470 MeV. Our results are renormalized non-perturbatively and the values are given in the MS-scheme at a scale mu=2 GeV.