http://arxiv.org/abs/1004.4866 Unification of gravity, gauge fields, and Higgs bosons A. Garrett Lisi, Lee Smolin, Simone Speziale 12 pages (Submitted on 27 Apr 2010) "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." EDIT: I now see that MTd2 flagged this new paper one minute earlier than I did. So as far as I am concerned this post can be deleted or merged into the thread which MTd2 started.