HIGH-ENERGY DENSITY IMPLICATIONS OF A GRAVITOWEAK UNIFICATION SCENARIO

'We discuss how a scenario recently proposed for the morphing of macroscopic gravit, tion into weak interactions at the at tometer scale affects our current understanding of high-energy density phenomena. We find that the Yukawa couplings of the fundamental fermions are directly related to their event horizons, setting an upper bound y(f) <= root 2 for their observability through gauge interactions. Particles With larger Yukawa you plings are not precluded, but should interact only gravitationally, providing a natural candidate for dark matter. Furthermore, the quantum vacuum contribution to the cosmological constant is reduced by several orders of magnitude with respect to the current estimates. The expected running of the Newtonian gravitational constant could provide a viable alternative scenario to the in stage of the Universe.