Testing Lorentz-symmetry violation via electroweak decays

TL;DR

This paper introduces CPT-odd Lorentz-symmetry violating couplings in the electroweak sector, modifies decay processes, and uses experimental data to set bounds on these violations.

Contribution

It proposes a new class of dimension-five operators causing Lorentz violation in electroweak interactions and derives bounds from decay process measurements.

Findings

Bounds on Lorentz-violating background vectors are $ extless{} 10^{-4}$ GeV$^{-1}$.

Modified decay rates are consistent with experimental data within bounds.

New operators provide a framework for testing Lorentz symmetry in electroweak processes.

Abstract

In this work we introduce CPT-odd non-minimal Lorentz-symmetry violating couplings to the electroweak sector modifying the interaction between leptons and gauge bosons. The vertex rules allow us to calculate tree-level processes modified by the presence of the novel dimension-five operators. For definitiveness, we investigate the $W$ decay into a lepton-neutrino pair, the $Z$ decay into pairs of charged and neutral leptons, as well as the decay of the muon. By comparing the experimental measurements on these processes to our results we are able to bound several combinations of the background 4-vectors to be $\lesssim 10^{-4} \, \mbox{GeV}^{-1}$.