Indirect constraints on the Georgi-Machacek model and implications for Higgs couplings

TL;DR

This paper updates constraints on the Georgi-Machacek model from B-physics and electroweak data, analyzing their impact on Higgs couplings and potential observable enhancements in Higgs production.

Contribution

It provides the first comprehensive analysis of indirect constraints on the model including recent B-physics data and explores their implications for Higgs coupling modifications.

Findings

Enhancements of Higgs production cross sections up to 39% are still viable.

Current LHC Higgs measurements may not detect these enhancements due to possible non-standard decays.

Updated constraints significantly restrict the parameter space of the Georgi-Machacek model.

Abstract

We update the indirect constraints on the Georgi-Machacek model from $B$-physics and electroweak precision observables, including new constraints from $b \to s \gamma$ and $B^0_s \to \mu^+ \mu^-$. We illustrate the effect of these constraints on the couplings of the Standard Model-like Higgs boson by performing scans using the most general scalar potential, subject to vacuum stability and perturbativity constraints. We find that simultaneous enhancements of all the Higgs production cross sections by up to 39\% are still allowed after imposing these constraints. LHC rate measurements on the Higgs pole could be blind to these enhancements if unobserved non-standard Higgs decays are present.