Active mass in relativistic gravity: theoretical interpretation of the Kreuzer experiment.
Abstract
A 1966 experiment performed by Kreuzer set an upper limit of 5 parts in 100,000 on the difference in the ratio of active to passive mass between fluorine and bromine. (Active mass of a body is the mass that generates gravity, while passive mass is the mass that responds to gravity.) A parameterized postNewtonian formalism for the spacetime metric of a system of charged point particles is introduced using parameters whose values vary from gravitation theory to gravitation theory. The prediction of this formalism for the active gravitational masses of fluorine and bromine nuclei is compared with the results of the Kreuzer experiment, and an upper limit is placed on a combination of these PPN parameters. By making a detailed comparison of the pointmass formalism with the standard perfectfluid PPN formalism, it is shown that for theories of gravitation whose perfectfluid equations are blind to the different forms of internal energy and pressure in the fluid, the perfectfluid PPN parameters must satisfy a certain constraint. It is also shown that any theory of gravity that possesses postNewtonian integral conservation laws for total momentum automatically agrees with the Kreuzer experiment.
 Publication:

The Astrophysical Journal
 Pub Date:
 February 1976
 DOI:
 10.1086/154164
 Bibcode:
 1976ApJ...204..224W
 Keywords:

 Charged Particles;
 Gravitation Theory;
 Particle Mass;
 Particle Theory;
 Relativity;
 Bromine;
 Conservation Laws;
 Equations Of Motion;
 Fluorine;
 Ideal Fluids;
 Maxwell Equation;
 Nuclei (Nuclear Physics);
 Particle Interactions;
 Astrophysics