  We point out that the expansion of the universe leads to a cosmological time
evolution of the vacuum expectation of the Higgs boson. Within the standard
model of particle physics, the cosmological time evolution of the vacuum
expectation of the Higgs leads to a cosmological time evolution of the masses
of the fermions and of the electroweak gauge bosons while the scale of Quantum
Chromodynamics (QCD) remains constant. Precise measurements of the cosmological
time evolution of $\mu=m_e/m_p$, where $m_e$ and $m_p$ are respectively the
electron and proton mass (which is essentially determined by the QCD scale),
therefore provide a test of the standard models of particle physics and of
cosmology. This ratio can be measured using modern atomic clocks.
