Revisiting Theories with Enhanced Higgs Couplings to Weak Gauge Bosons

Abstract

Based on recent LHC Higgs analyses and in anticipation of future results we revisit theories where Higgs bosons can couple to weak gauge bosons with enhanced strength relative to the Standard Model value. Specifically, we look at the Georgi-Machacek model and its generalizations where higher "spin" representations of SU(2)_L break electroweak symmetry while maintaining custodial SU(2). In these theories, there is not only a Higgs-like boson but partner Higgs scalars transforming under representations of custodial SU(2), leading to a rich phenomenology. These theories serve as a consistent theoretical and experimental framework to explain enhanced couplings to gauge bosons, including fermiophobic Higgses. We focus on the phenomenology of a neutral scalar partner to the Higgs, which is determined once the Higgs couplings are specified. Depending on the parameter space, this partner could have i) enhanced fermion and gauge boson couplings and should be searched for at high mass (> 600 GeV), ii) have suppressed couplings and could be searched for at lower masses, where the Standard Model Higgs has already been ruled out, and iii) have fermiophilic couplings, where it can be searched for in heavy Higgs and top resonance searches. In the first two regions, the partner also has substantial decay rates into a pair of Higgs bosons. We touch briefly on the more model-dependent effects of the nontrivial SU(2)_C multiplets, which have exotic signals, such as a doubly-charged Higgs. We also discuss how the loop induced effects of these scalars tend to reduce the Higgs decay rate to photons, adding an additional uncertainty when extracting the couplings for the Higgs boson.

9 pages, 9 figures, revtex4; v2, references added

References in corpus (4)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• Combined search for the Standard Model Higgs boson in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
• Unitarity bounds in the Higgs model including triplet fields with custodial symmetry

Cited by in corpus (12)

• Complete Higgs Sector Constraints on Dimension-6 Operators
• The decoupling limit in the Georgi-Machacek model
• LHC HXSWG interim recommendations to explore the coupling structure of a Higgs-like particle
• Indirect constraints on the Georgi-Machacek model and implications for Higgs couplings
• Little Higgs theory confronted with the LHC Higgs data
• The Effective Standard Model after LHC Run I
• Real singlet scalar dark matter extension of the Georgi-Machacek model
• Supersymmetric Custodial Higgs Triplets and the Breaking of Universality
• Distinguishing `Higgs' Spin Hypotheses using gamma gamma and WW* Decays
• Searching for the doubly-charged Higgs bosons in the Georgi-Machacek model at the electron-proton colliders
• Searching for the heavy custodial fiveplet Higgs in the Georgi-Machacek model at the International Linear Collider
• Does unitarity imply finiteness of electroweak oblique corrections at one-loop? - constraining extra neutral Higgs bosons -