# Limits on Lorentz violation from charged-pion decay

Source: [Limits on Lorentz violation from charged-pion decay](<https://www.sota2.com/research/paper/68fa2d5e1e209131ce8586bf>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T16:12:04.426Z

Authors: J. P. Noordmans, K. K. Vos

Published: 2014-04-30T08:35:35.000Z

## Abstract

Charged-pion decay offers many opportunities to study Lorentz violation. Using an effective field theory approach, we study Lorentz violation in the lepton, W-boson, and quark sectors and derive the differential pion-decay rate, including muon polarization. Using coordinate redefinitions we are able to relate the first-generation quark sector, in which no bounds were previously reported, to the lepton and W-boson sector. This facilitates a tractable calculation, enabling us to place bounds on the level of $10^{-4}$ on first-generation quark parameters. Our expression for the pion-decay rate can be used to constrain Lorentz violation in future experiments.

## Recorded benchmark results

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1404.7629>)

[PDF](<https://arxiv.org/pdf/1404.7629.pdf>)