PARTICLE MASSES IN KALUZA-KLEIN-GORDON THEORY AND THE REALITY OF EXTRA DIMENSIONS

To see how the effective 4-D mass of a particle is affected by the geo metry of an ND space, we take the Klein-Gordon equation in 5-D and eva luate it in PD using two exact solutions of 5-D Kaluza-Klein theory. T he mass (squared) turns out to be complex if the theory is independent of the extra coordinate, but can be made real if the wave function de pends on an extra dimension which is physical. These results have sign ificant implications for 10-D superstring theory.