Investigation of the structure of the Standard Model effective potential at very large field strengths opens a window towards new phenomena and can reveal properties of the UV completion of the SM. The map of the lifetimes of the vacua of the SM enhanced by nonrenormalizable scalar couplings has been compiled to show how new interactions modify stability of the electroweak vacuum. Whereas it is possible to stabilize the SM by adding Planck scale suppressed interactions and taking into account running of the new couplings, the generic effect is shortening the lifetime and hence further destabilisation of the SM electroweak vacuum. These findings have been illustrated with phase diagrams of modified SM-like models. It has been demonstrated that stabilisation can be achieved by lowering the suppression scale of higher order operators while picking up such combinations of new couplings, which do not deepen the new minima of the potential. Our results show the dependence of the lifetime of the electroweak minimum on the magnitude of the new couplings, including cases with very small couplings (which means very large effective suppression scale) and couplings vastly different in magnitude (which corresponds to two different suppression scales).

In this paper we have made a map of the vacua in the SM extended by nonrenormalisable scalar couplings, taking into account the running of the new couplings and going beyond the standard assumptions taken when calculating the lifetime of the metastable vacuum. Usually, one uses certain quasi-analytic approximations of the effective potential, \cite{WeinbergLee}, for the purpose of calculating the tunneling rate. In particular, one uses as the departure point the calculation for the quartic-like form of the effective potential at large field strenghts, while in the modified scalar potential it is the order 6 or order 8 coupling which naively dominates the potential in the large field domain. It is important to check the validity of such approximation and to search through a relatively wide scope of new couplings to find the actual behaviour of the scalar potential. The ultimate tool in this case is the direct numerical analysis, which however is not so straightforward because of the flatness of the effective potential. In this paper we present currently available results of such extended analysis of the modified SM scalar potential. It turns out that the simplified analytical approach represents reasonably well the actual numerical results. In general, we confirm that it is relatively easy to destabilise the SM with the help of the Planck scale suppressed scalar operators. While it is possible to stabilise the SM by adding such higher dimensional interactions and taking into account running of the new couplings, the generic effect is shortening the lifetime and hence further destabilisation of the SM electroweak vaccuum. This conclusion has been illustrated with the phase diagrams of modified SM-like models. It has been demonstrated that effective stabilisation can be achieved by lowering the suppression scale of higher order operators while picking up such combinations of new couplings, which do not deepen the new minima of the potential. Our results show the dependence of the lifetime of the electroweak minimum on the magnitude of the new couplings, including cases with very small couplings (which means very large effective suppression scale) and couplings vastly different in magnitude (which corresponds to two different suppression scales).