Violation of the Landau-Yang theorem from Infrared Lorentz Symmetry Breaking

Abstract

Lorentz symmetry forbids decays of massive spin-1 particle like the $Z^0$ into two massless photons, a result known as the Landau-Yang theorem. But it is known that infrared effects can break Lorentz invariance. Employing the construction of Mund et. al. \cite{MRS} which incorporated this Lorentz violation, we propose an interaction leading to the decay $Z^0\to 2\gamma$ and study the dependence of the decay on the parameter of this Lorentz violation.

Comments: Accepted for publication in JHEP, title changed in Journal, references added , 10 pages , 2 figures