New Experimental Test of Coulomb's Law: A Laboratory Upper Limit on the Photon Rest Mass
Abstract
A highfrequency test of Coulomb's law is described. The sensitivity of the experiment is given in terms of a finite photon rest mass using the Proca equations. The null result of our measurement expressed in the form of the photon rest mass squared is μ^{2}=(1.04+/1.2)×10^{19} cm^{2}. Expressed as a deviation from Coulomb's law of the form 1r^{2+q}, our experiment gives q=(2.7+/3.1)×10^{16}. This result extends the validity of Coulomb's law by two orders of magnitude.
 Publication:

Physical Review Letters
 Pub Date:
 March 1971
 DOI:
 10.1103/PhysRevLett.26.721
 Bibcode:
 1971PhRvL..26..721W