A "magnetic" photon hypothesis associated with magnetic monopoles is tested experimentally. These photons are predicted to easily penetrate metal. Experimentally the optical transmittance T of a metal foil was less than 2 x 10^-17. The hypothesis is not supported since it predicts T = 2 x 10^-12.
@article{arxiv.physics/0405148,
title = {Experimental test of magnetic photons},
author = {R. S. Lakes},
journal= {arXiv preprint arXiv:physics/0405148},
year = {2009}
}