Chiral extrapolation of nucleon magnetic moments at next-to-leading-order

TL;DR

This paper extends chiral effective field theory to next-to-leading-order to improve the extrapolation of nucleon magnetic moments from quenched to full QCD, highlighting the importance of higher-order corrections.

Contribution

It introduces a formalism incorporating NLO loop contributions for more accurate nucleon magnetic moment predictions in QCD extrapolations.

Findings

NLO corrections significantly affect magnetic moment predictions.

The formalism allows correction of quenched QCD results to full QCD.

Higher-order effects are crucial for precise chiral extrapolations.

Abstract

Nucleon magnetic moments display a rich nonanalytic dependence on the quark mass in both quenched and full QCD. They provide a forum for a detailed examination of the connection between quenched and full QCD made possible through the formalism of finite-range regularised chiral effective field theory. By defining meson-cloud and core contributions through the careful selection of a regularisation scale, one can correct the meson cloud of quenched QCD to make full QCD predictions. Whereas past success is based on unquenching the leading-order loop contributions, here we extend and test the formalism including next to leading-order (NLO) loop contributions. We discuss the subtleties associated with working at NLO and illustrate the role of higher-order corrections.