K20 and the Equivalence Principle

Phys. Rev. 121, 311 – Published 1 January 1961
Myron L. Good


It is shown that the existence of the long-lived neutral K meson, and the absence of its decay into two pions, establishes that the gravitational masses of the K0 and K¯0 are equal to a few parts in 10-10 of the K inertial mass. This is of interest since the K¯0 is the antiparticle of the K0, and is not identical with the K0. The gravitational mass of such a nonidentical antiparticle has never been directly measured.

Also, the K¯0 has opposite strangeness to the K0. Thus the argument rules out any linear dependence of the gravitational mass on the strangeness quantum number, a point on which all previous experiments say nothing.

These observations are in accord with, and serve as a confirmation of, the equivalence principle of Einstein.

DOI: http://dx.doi.org/10.1103/PhysRev.121.311

  • Received 18 July 1960
  • Published in the issue dated January 1961

© 1961 The American Physical Society

Authors & Affiliations

Myron L. Good

  • University of Wisconsin, Madison, Wisconsin

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