Abstract
One of the simplest extensions of the Standard Model (SM) is the addition of a scalar gauge singlet, S. If S is not forbidden by a symmetry from mixing with the Standard Model Higgs boson, the mixing will generate non-SM rates for Higgs production and decays. In general, there could also be unknown high energy physics that generates additional effective low energy interactions. We show that interference effects between the scalar resonance of the singlet model and the effective field theory (EFT) operators can have significant effects in the Higgs sector. We examine a non-$Z_2$ symmetric scalar singlet model and demonstrate that a fit to the 125 GeV Higgs boson couplings and to limits on high mass resonances, S, exhibit an interesting structure and possible large cancellations of effects between the resonance contribution and the new EFT interactions, that invalidate conclusions based on the renormalizable singlet model alone.
Highlights
Among the simplest extensions of the Standard Model (SM) is the addition of a gauge singlet scalar particle, S
The source of these effective interactions is not relevant for our discussion and our focus is on the consequences of the interference effects between the heavy scalar resonance and the effective field theory (EFT) operators
We examined the effects on Higgs physics of a gauge singlet scalar which mixes with the SM-like 125 GeV Higgs boson when the theory is augmented by EFT operators coupling the singlet scalar to SM gauge bosons
Summary
Among the simplest extensions of the Standard Model (SM) is the addition of a gauge singlet scalar particle, S. There can be additional interactions between the S and the gauge bosons, which can be parameterized as effective field theory (EFT) dimension-5 couplings The source of these effective interactions is not relevant for our discussion and our focus is on the consequences of the interference effects between the heavy scalar resonance and the EFT operators. Novel features of our analysis are the insistence that the parameters satisfy the minimization condition of the potential and our inclusion of interference effects between the SM contributions to the Higgs widths and the contributions from the EFT interactions. These interference effects can be large and significantly change the allowed regions of parameter space.
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