A high-frequency 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 . Expressed as a deviation from Coulomb's law of the form , our experiment gives . This result extends the validity of Coulomb's law by two orders of magnitude.
- Received 22 January 1971
- Published in the issue dated 22 March 1971
© 1971 The American Physical Society