Lorentz-violating neutral-pion decays in isotropic modified Maxwell theory

TL;DR

This paper investigates how Lorentz violation in the photon sector affects neutral pion decay rates, revealing modifications that depend on the pion's momentum and the Lorentz-violating parameter.

Contribution

It provides the first calculation of neutral pion decay into nonstandard photons within an isotropic Lorentz-violating extension of the Standard Model.

Findings

Decay rate depends on pion momentum and Lorentz-violating parameter

Negative Lorentz-violating parameter corresponds to faster photon phase velocity

Results can constrain Lorentz violation through pion decay observations

Abstract

We consider an extension of the Standard Model with isotropic nonbirefringent Lorentz violation in the photon sector and restrict the discussion to the case of a "fast" photon with a phase velocity larger than the maximum attainable velocity of the quarks and leptons. With our conventions, this case corresponds to a negative Lorentz-violating parameter $\kappa$ in the action. The decay rate of a neutral pion into two nonstandard photons is calculated as a function of the 3-momentum of the initial pion and the negative Lorentz-violating parameter $\kappa$ of the final photons.