Electromagnetic Form Factors with FLIC Fermions

TL;DR

This paper introduces FLIC fermions, a new nonperturbative O(a) improvement technique, enabling efficient lattice QCD simulations of baryon form factors at light quark masses, revealing chiral nonanalytic behaviors.

Contribution

The paper presents FLIC fermions as a novel nonperturbative O(a) improved action that simplifies calculations of baryon form factors at light quark masses on large lattices.

Findings

First simulation of baryon form factors at light quark masses on large volume lattice

Extraction of magnetic moments, charge and magnetic radii from form factors

Observation of chiral nonanalytic behavior in light quark mass regime

Abstract

The Fat-Link Irrelevant Clover (FLIC) fermion action provides a new form of nonperturbative O(a) improvement and allows efficient access to the light quark-mass regime. FLIC fermions enable the construction of the nonperturbatively O(a)-improved conserved vector current without the difficulties associated with the fine tuning of the improvement coefficients. The simulations are performed with an O(a^2) mean-field improved plaquette-plus-rectangle gluon action on a 20^3 x 40 lattice with a lattice spacing of 0.128 fm, enabling the first simulation of baryon form factors at light quark masses on a large volume lattice. Magnetic moments, electric charge radii and magnetic radii are extracted from these form factors, and show interesting chiral nonanalytic behavior in the light quark mass regime.