Nucleon Magnetic Moments, their Quark Mass Dependence and Lattice QCD Extrapolations

TL;DR

This paper investigates how nucleon magnetic moments depend on quark mass using chiral effective field theory, fitting lattice data to produce reliable extrapolations to physical values.

Contribution

It introduces a detailed chiral effective field theory approach with explicit degrees of freedom to model nucleon magnetic moments and fits lattice data for accurate quark mass extrapolations.

Findings

Successful fit of lattice data in the isovector sector

Well-behaved extrapolation connecting lattice, chiral limit, and experiment

Comparison with Pade formula of the Adelaide group

Abstract

We calculate the quark mass dependence of both isovector and isoscalar anomalous magnetic moments of the nucleon in a chiral effective field theory with explicit pion, nucleon and Delta(1232) degrees of freedom to leading-one-loop order. In the isovector sector we fit 3 unknown couplings of the effective Lagrangian to available lattice data and obtain a surprisingly well-behaved extrapolation function connecting the chiral limit, experimental data and the lattice simulations. We also discuss the polynomial quark mass dependence in the isoscalar sector and finally compare with the Pade formula of the Adelaide group.