Vacuum stability and the scaling behaviour of the Higgs-curvature coupling

Abstract: Stability of the Higgs vacuum during early universe inflation is dependent on how the Higgs couples to the spacetime curvature. Limits on the curvature coupling parameter at the electroweak scale $\xi_{EW}$ are shown to be consistent only when quantum gravity effects are included and a covariant quantisation procedure, such as Vilkovisky-DeWitt, is adopted. Stability requires $\xi_{EW}>-0.03$ for a top quark mass $M_t=173.34\,{\rm GeV}$.