A Variational Study of the Nucleon Wavefunction

TL;DR

This paper investigates the nucleon wavefunction using variational methods on the lattice, exploring how different parameters affect the overlap with trial functions, and finds high overlaps without evidence of diquark substructure.

Contribution

It introduces a variational approach to study nucleon structure on the lattice, analyzing effects of source smearing, gauge smearing, and substructure inclusion.

Findings

Achieved overlaps up to 80% with quenched Wilson fermions.

No evidence found for diquark substructure in the nucleon.

Explored effects of spatial extent and gauge smearing on wavefunction overlap.

Abstract

The structure of the nucleon is studied variationally on the lattice by maximizing the overlap between the nucleon and a trial function generated by an interpolating field containing variational parameters. We examine the effect of the spatial extent of smeared quark sources, the degree of gauge field smearing, the positions of smeared quark sources, inclusion of lower Dirac components and of diquark substructure. Exploratory calculations with quenched Wilson fermions at a pion mass of 900 MeV achieved overlaps as high as 80%, and there was no evidence of diquark substructure.