Effective potential (in)stability and lower bounds on the scalar (Higgs) mass

TL;DR

This paper challenges the common belief that top loop corrections destabilize the Higgs potential, showing that stability is intrinsic and providing revised lower bounds on the Higgs mass, especially if new physics is near the TeV scale.

Contribution

It demonstrates that the apparent instability of the Higgs potential is due to invalid extrapolation, establishing stability as an inherent property and deriving new lower bounds on the Higgs mass.

Findings

Stability is intrinsic, not an extrapolation artifact.

Revised lower bounds on Higgs mass for TeV-scale new physics.

Excludes the meta-stability scenario for the electroweak vacuum.

Abstract

It is widely believed that the top loop corrections to the Higgs effective potential destabilise the electroweak (EW) vacuum and that, imposing stability, lower bounds on the Higgs mass can be derived. With the help of a scalar-Yukawa model, we show that this apparent instability is due to the extrapolation of the potential into a region where it is no longer valid. Stability turns out to be an intrinsic property of the theory (rather than an additional constraint to be imposed on it). However, lower bounds for the Higgs mass can still be derived with the help of a criterium dictated by the properties of the potential itself. If the scale of new physics lies in the Tev region, sizeable differences with the usual bounds are found. Finally, our results exclude the alternative meta-stability scenario, according to which we might be living in a sufficiently long lived meta-stable EW vacuum.