2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179651If photons had a small electric charge $Q_γ$ 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 $Q_γ/e\lapprox10^{-29}$.3 pages, LaTeXHigh Energy Physics - Phenomenologytext