Current-Enhanced Excited States in Lattice QCD Three-Point Functions

TL;DR

This paper introduces a method to identify and understand excited-state contamination in lattice QCD three-point functions, improving the accuracy of hadron structure measurements by analyzing how currents and kinematics influence excited states.

Contribution

It presents a novel argument, inspired by current-meson dominance, combined with the variational method, to determine which excited states are enhanced in lattice QCD calculations.

Findings

Numerical evidence supports the argument across multiple hadronic channels.

Provides practical guidance for accounting for excited-state effects.

Enhances conceptual understanding of 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 letter, we present a general argument, inspired by current-meson dominance and implemented through the variational method, to identify which excited states are enhanced by the choice of the inserted current and kinematics. The argument is supported by numerical evidence across multiple hadronic channels and provides both a conceptual understanding and practical guidance to account for excited-state effects in hadron three-point function analyses.