Katy Hartling

The decoupling limit in the Georgi-Machacek model

We study the most general scalar potential of the Georgi-Machacek model, which adds isospin-triplet scalars to the Standard Model (SM) in a way that preserves custodial SU(2) symmetry. We show that this model possesses a decoupling limit, in which the predominantly-triplet states become heavy and degenerate while the couplings of the remaining light neutral scalar approach those of the SM Higgs boson. We find that the SM-like Higgs boson couplings to fermion pairs and gauge boson pairs can deviate from their SM values by corrections as large as

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

\mathcal{O}({v}^{2}/{M}_{\text{new}}^{2})

Constraining models with a large scalar multiplet

, where

Automatic predictions in the Georgi-Machacek model at next-to-leading order accuracy

v

High-energy suppression of the Higgsstrahlung cross section in the Minimal Composite Higgs Model

is the SM Higgs vacuum expectation value and

Two viable large scalar multiplet models with a Z

{M}_{\text{new}}

_2

is the mass scale of the predominantly-triplet states. In particular, the SM-like Higgs boson couplings to

symmetry

W

GMCALC: a calculator for the Georgi-Machacek model

and

arXiv : Scalar decays to

Z