Diminished Upper Bounds on the Unification Mass Scales for Heavy Higgs Boson Masses

TL;DR

This paper analyzes high-order loop contributions to the Higgs quartic coupling in the Standard Model, showing they lower the unification mass bounds and suggest earlier nonperturbative behavior in the Higgs sector.

Contribution

It provides new insights into how 3- to 5-loop effects significantly impact the evolution of the Higgs coupling and unification bounds, which was not previously understood.

Findings

Higher loop contributions accelerate the growth of the Higgs quartic coupling.

These effects lower the unification mass scale for heavy Higgs bosons.

The Higgs coupling becomes nonperturbative at lower energies than previously estimated.

Abstract

We consider dominant 3-, 4-, and 5-loop contributions to $\lambda$, the quartic scalar coupling-constant's $\beta$-function in the Standard Model. We find that these terms accelerate the evolution of $\lambda$ to nonperturbative values, thereby lowering the unification bound for which scalar-couplings are still perturbative. We also find that these higher order contributions imply a substantial lowering of $\lambda$ itself before the anticipated onset of nonperturbative physics in the Higgs sector.