Unity of Fundamental Interactions

The vector representation of the linearized gravitational field (the graviton field) or the so called quantum gravitodynamics which describes the motion of masses in a weak gravitational field is employed to understand the unity of the four known interactions. We propose a gauge group SU(3)xSU(2)xU(1)xU(1) for such a unified field theory. In this paper we study the SU(2)xU(1)xU(1) sector of the theory and in analogy to the electroweak mixing angle we define a gravitoweak mixing angle. The unified gauge field theory predicts the existence of three massive vector bosons, the Y+/- and the X^0. and two massless vector bosons, the photon and the graviton (in its vector representation). We determine the mass spectrum of the Y+/- and the X^0 and predict a modification to the fine structure constant under unified field conditions. Furthermore, we briefly discuss the implications of the extended object formulation for the gauge hierarchy problem.