Lattice QCD Study of Pion Electroproduction and Weak Production from a Nucleon

TL;DR

This paper uses lattice QCD to calculate pion production amplitudes near threshold, providing insights into chiral dynamics and nucleon structure by comparing numerical results with experimental data and theoretical predictions.

Contribution

It introduces a novel lattice QCD technique for analyzing pion electroproduction and weak production, including spin projection and operator construction near the physical pion mass.

Findings

Lattice results agree with experimental data within uncertainties.

The study provides new multipole amplitude calculations at threshold.

Results support low-energy theorems with one-loop corrections.

Abstract

Quantum fluctuations in QCD influence nucleon structure and interactions, with pion production serving as a key probe of chiral dynamics. In this study, we present a lattice QCD calculation of multipole amplitudes at threshold, related to both pion electroproduction and weak production from a nucleon, using two gauge ensembles near the physical pion mass. We develop a technique for spin projection and construct multiple operators for analyzing the generalized eigenvalue problem in both the nucleon-pion system in the center-of-mass frame and the nucleon system with nonzero momentum. The numerical lattice results are then compared with those extracted from experimental data and predicted by low-energy theorems incorporating one-loop corrections.