Abstract
With the Higgs search program already quite mature, there is the exciting possibility of discovering a new particle with rates near that of the SM Higgs. We consider models with a signal in γγ below the SM Higgs mass. We discuss singlet models with additional vectorlike matter, but argue that a Type-I two Higgs doublet model can more easily provide detectable rates. In such scenarios, in regions of moderate-to-strong fermiophobia, the enhanced γγ branching ratio allows signals from V H+VBF production to yield σ × BRγγ comparable to total SM rates and would thus be detectable. Light H production can be dominated via rare top decays t → bH+ → bW∗H, which provides an even more efficient means of production. We also consider this in the context of various Higgs anomalies, specifically the recent 2.9 σ (local) CMS excess at 95 GeV, the LEP Higgs excess near the same mass, and excesses in toverline{t}h searches at Tevatron and LHC. We find regions of parameter space that can meet all simultaneously. An implication of the Type-I scenario is that any γγ excess should be associated with additional elements that could reduce background, including b-jets, forward jets or signs of vector boson production.
Highlights
We conclude, and emphasize how, irrespective of any anomaly, these models provide insights that can direct improvements to existing searches at the LHC
It is worth considering what kinds of models could achieve this, and whether they predict any new features that could improve the searches further. Using this as a concrete target, one can ask what sorts of models can create a diphoton resonance with a cross section approaching that of the SM Higgs boson at the LHC.1
With the increasing sensitivity of Higgs searches, we confront the prospect of the discovery of new particles with Higgs-like properties
Summary
The CMS collaboration has reported a significant improvement in its search for the diphoton resonances in the light mass regime (70 − 110 GeV) [1]. With 35.9 fb−1 at 13 TeV, they have remarkably passed the critical threshold of being sensitive to models with SM-strength in this mass regime, opening up sensitivity to new models In this analysis, CMS has reported a 2.9 σ (local) excess at 95.3 GeV. We know from LEP that no SM-like Higgs boson exists at that mass [4] It is worth considering what kinds of models could achieve this, and whether they predict any new features that could improve the searches further. Using this as a concrete target, one can ask what sorts of models can create a diphoton resonance with a cross section approaching that of the SM Higgs boson at the LHC.
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