Limits on new forces coexisting with electromagnetism

Harry Thomas Kloor, Purdue University

Abstract

We consider the limits arising from different electromagnetic systems on the existence of a possible new electromagnetic analog of the fifth force. Although such a force may have no intrinsic connection to electromagnetism (or gravity), its effects could be manifested through various anomalies in electromagnetic systems, for appropriate values of the coupling strength and range. Our work generalizes that of Bartlett and Logl (who considered the case of a massive vector field co-existing with massless electrodynamics) to encompass a broad class of phenomenological interactions mediated by both scalar and vector exchanges. By combining data from both gravitational and electromagnetic systems, one can eventually set limits on a new force whose range $\lambda$ extends from the subatomic scale $\rm (\lambda\approx10\sp{-15}m)$ to the astrophysical scale $\rm (\lambda\approx10\sp{22}m).$ A new geomagnetic limit on the photon mass $m\sb\gamma$ is derived from an analysis of satellite measurements of the Earth's magnetic field $\vec{H}.$ The primary effect of a nonzero photon mass is to generate an additional contribution to $\vec{H}$ resembling that from an external source. We find $m\sb\gamma\le8\times10\sp{-16}eV/c\sp2 = 1\times10\sp{-48}g = 4\times10\sp{-9}m\sp{-1}.$ Using Chibisov's method (80) and the discovery of intracluster magnetic fields, we also set a new indirect upper limit on the mass of the photon of $m\sb\gamma\le1\times10\sp{-28}eV/c\sp2 = 2\times10\sp{-61}g.$ A general multipole expansion for radiation from massive vector and scalar fields is developed for periodic sources. This formalism is then combined with data on the binary pulsar PSR 1913+16 to set limits on the electric charge of astrophysical bodies, and on the coupling strength strengths of new weak gravity-like forces.

Degree

Ph.D.

Advisors

Fischbach, Purdue University.

Subject Area

Chemistry|Chemistry

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