Pulsar Bound on the Photon Electric Charge Reexamined

Abstract

If photons had a small electric charge $Q_{\gamma }$ their path in the galactic magnetic field would be curved, leading to a time delay between photons of different frequency from a distant source. Cocconi's previous application of this argument led to a limit which is too restrictive by a factor of about 200; the corrected bound is $Q_{\gamma }/e\text{lapprox}10^{-29}$.

Comments: 3 pages, LaTeX