More Constraints on the Georgi-Machacek Model

TL;DR

This paper thoroughly examines the parameter space of the Georgi-Machacek model, applying various theoretical and experimental constraints, and finds that a significant portion is excluded by vacuum stability issues and collider search limits.

Contribution

It provides a comprehensive analysis of the GM model's parameter space considering multiple constraints, including vacuum stability and collider search results, highlighting regions that are excluded or viable.

Findings

Approximately 40% of the parameter space is excluded by unwanted minima.

Heavy resonance searches significantly constrain the model.

Future collider searches could further restrict the parameter space.

Abstract

In this work, we investigate the parameter space of the Georgi-Machacek (GM) model, where we consider many theoretical and experimental constraints such as the perturbativity, vacuum stability, unitarity, electroweak precision tests, the Higgs di-photon decay, the Higgs total decay width and the LHC measurements of the signal strengths of the SM-like Higgs boson $h$ in addition to the constraints from doubly charged Higgs bosons and Drell-Yan di-photon production and the indirect constraint from the $b\to s$ transition processes. We investigate also the possibility that the electroweak vacuum could be destabilized by unwanted wrong minima that may violate the CP and/or the electric charge symmetries. We found that about 40 \% of the parameter space that fulfills the above mentioned constraints; are excluded by these unwanted minima. In addition, we found that the negative searches for a heavy resonance could exclude a significant part of the viable parameter space; and future searches could exclude more regions in the parameter space.