A Bound on Violations of Lorentz Invariance

Recently Coleman and Glashow [1] have developed a model which allows the introduction of a small violation of Lorentz invariance. Observational signatures arise because this interaction also violates flavor conservation and allows the radiative decay of the muon, µ → e + γ , whose branching ratio increases as b γ 4 where γ is the Lorentz factor of the muon with respect to the reference frame in which the dipole anisotropy of the universal microwave radiation vanishes. In this paper we place a bound of b < 10 − 25 based on ob-servations of horizontal air showers with n e ≥ 5 × 10 6 . With such small values of b the proposed radiative decay of the muon will not affect the functioning of the muon collider. transition µ → e +