Electroweak vacuum instability and spacetime curvature

When extrapolated to high energies, the Standard Model of particle physics predicts that for the measured parameter values the current vacuum state of the Universe is unstable and would eventually decay to a true vacuum state with very high negative energy density. The rate of this decay process depends on spacetime curvature both through quantum loop corrections and through the tree-level Higgs-curvature coupling, which is required by renormalisability but whose is value is currently very poorly constrained. I present results showing that in the current nearly Minkowski spacetime, the Higgs-curvature coupling suppresses the decay rate, but in the highly curved spacetime of the early Universe, the rate can be significantly enhanced depending on the value of the Higgs-curvature coupling. In principle, the survival of the Universe through inflation and (p)reheating places can constrain value of the Higgs-curvature coupling 15 orders of magnitude better than the current best experimental bounds.