Unification of gravity, gauge fields and Higgs bosons

We consider a diffeomorphism invariant theory of a gauge field valued in a Lie algebra that breaks spontaneously to the direct sum of the spacetime Lorentz algebra, a Yang-Mills algebra and their complement. Beginning with a fully gauge invariant action-an extension of the Plebanski action for general relativity-we recover the action for gravity, Yang-Mills and Higgs fields. The low-energy coupling constants, obtained after symmetry breaking, are all functions of the single parameter present in the initial action and the vacuum expectation value of the Higgs.