Chiral effective field theory beyond the power-counting regime

TL;DR

This paper introduces new techniques to identify the chiral power-counting regime and extract an intrinsic energy scale from lattice QCD results, enabling accurate descriptions beyond traditional limits.

Contribution

It presents a novel approach using finite-range regularization to determine an optimal scale, extending the applicability of chiral effective field theory beyond the power-counting regime.

Findings

Optimal regularization scale can be extracted from lattice data.

The approach handles scheme dependence effectively.

Preliminary results for nucleon magnetic moment are consistent.

Abstract

Novel techniques are presented, which identify the chiral power-counting regime (PCR), and realize the existence of an intrinsic energy scale embedded in lattice QCD results that extend outside the PCR. The nucleon mass is considered as a benchmark for illustrating this new approach. Using finite-range regularization, an optimal regularization scale can be extracted from lattice simulation results by analyzing the renormalization of the low energy coefficients. The optimal scale allows a description of lattice simulation results that extend beyond the PCR by quantifying and thus handling any scheme-dependence. Preliminary results for the nucleon magnetic moment are also examined, and a consistent optimal regularization scale is obtained. This indicates the existence of an intrinsic scale corresponding to the finite size of the source of the pion cloud.