The role that the auxiliary scalar field Ï• played in Brans-Dicke
cosmology is discussed. If a constant vacuum energy is assumed to be the origin
of dark energy, then the corresponding density parameter would be a quantity
varying with Ï•; and almost all of the fundamental components of our
universe can be unified into the dynamical equation for Ï•. As a
generalization of Brans-Dicke theory, we propose a new gravity theory with a
complex scalar field Ï• which is coupled to the cosmological curvature
scalar. Through such a coupling, the Higgs mechanism is naturally incorporated
into the evolution of the universe, and a running density of the field vacuum
energy is obtained which may release the particle standard model from the
rigorous cosmological constant problem in some sense. Our model predicts a
running mass scale of the fundamental particles in which the gauge symmetry
breaks spontaneously. The running speed of the mass scale in our case could
survive all existing experiments.Comment: 6 page