New method for calculating electromagnetic effects in semileptonic beta-decays of mesons

TL;DR

This paper develops a new approach to calculate electromagnetic effects in semileptonic meson decays using lattice QCD, aiming to improve precision in fundamental parameters and address current anomalies in particle physics.

Contribution

It introduces a method to relate hadronic matrix elements to low-energy constants in Chiral Perturbation Theory and proposes their calculation via lattice QCD, enhancing precision in electroweak measurements.

Findings

Framework for relating matrix elements to low-energy constants

Proposal for lattice QCD calculations of these constants

Potential impact on understanding CKM matrix anomalies

Abstract

We construct several classes of hadronic matrix elements and relate them to the low-energy constants in Chiral Perturbation Theory that describe the electromagnetic effects in the semileptonic beta decay of the pion and the kaon. We propose to calculate them using lattice QCD, and argue that such a calculation will make an immediate impact to a number of interesting topics at the precision frontier, including the outstanding anomalies in $|V_{us}|$ and the top-row Cabibbo-Kobayashi-Maskawa matrix unitarity.