Evidence of current-enhanced excited states in lattice QCD three-point functions

TL;DR

This paper introduces a new mechanism, supported by numerical and theoretical evidence, to identify and control excited-state contamination in lattice QCD three-point functions, improving the accuracy of hadron structure measurements.

Contribution

It presents a general, current-enhanced excited-state identification method using the variational approach, with practical guidance for lattice QCD analyses.

Findings

Numerical evidence supports the mechanism across hadronic channels.

Predictions from chiral perturbation theory validate the approach.

Provides practical tools for reducing excited-state contamination.

Abstract

Excited-state contamination remains one of the leading sources of systematic uncertainty in the precise determination of hadron structure observables from lattice QCD. In this work, I present a general mechanism, motivated by meson dominance and implemented through the variational method, that identifies which excited states are enhanced by the choice of inserted current and kinematics. The argument is supported by numerical evidence and predictions from chiral perturbation theory across different hadronic channels, in particular in the nucleon sector, and provides both conceptual insight and practical guidance for controlling excited-state effects in hadron three-point function analyses.