In an expanding universe, the vacuum energy density ρΛ is expected to be a dynamical quantity. In quantum field theory in curved spacetime, ρΛ should exhibit a slow evolution, determined by the expansion rate of the universe H. Recent measurements on the time variation of the fine-structure constant and of the proton–electron mass ratio suggest that the basic quantities of the standard model, such as the QCD scale parameter ΛQCD, may not be conserved in the course of the cosmological evolution. The masses of the nucleons mN and of the atomic nuclei would also be affected. Matter is not conserved in such a universe. These measurements can be interpreted as a leakage of matter into vacuum or vice versa. We point out that the amount of leakage necessary to explain the measured value of could be of the same order of magnitude as the observationally allowed value of , with a possible contribution from the dark matter particles. The dark energy in our universe could be the dynamical vacuum energy in interaction with ordinary baryonic matter as well as with dark matter.

We discuss an alternative version of the electroweak standard model, in which only the heavy t quark, not the light fermions, couples to the Higgs boson with a strength given by the standard model. The Higgs particle decays dominantly into two gluons jets. The branching ratio for the 2γ decay is about 3.5%. The Higgs particle would be a narrow object (width about 60 KeV), and its mass might be consistent with the value given by typical estimates of radiative effects measured by the LEP experiments.