Cosmological Searches for Photon Velocity Oscillations
arXiv:astro-ph/9803202 · doi:10.1016/S0370-2693(98)00482-1
Abstract
We posit a second massless photon, uncoupled to known forms of matter but undergoing Lorentz non-invariant velocity mixing with ordinary photons. Our speculation within a speculation suffers from the sin of implausibility but enjoys the virtue of verifiability. To avoid unacceptable distortion of the well-measured microwave background spectrum, the velocity difference of the photons cannot exceed . Stronger constraints (or observable effects!) can arise from optical measurements of distant sources.
4 pages, TEX with harvmac macros