Light signals from a lighter Higgs

Journal Article · 07 August 2018 · Journal of High Energy Physics (Online)

DOI: https://doi.org/10.1007/JHEP08(2018)025 · OSTI ID:1463681

Fox, Patrick J. ^[1]; Weiner, Neal ^[2]

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1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2. New York Univ. (NYU), New York, NY (United States); Flatiron Institute, New York, NY (United States)

Here, 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 $$\gamma \gamma$$ below the SM Higgs mass, taking the recent $$2.9\, \sigma$$ (local) CMS excess at 95 GeV as a target. We discuss singlet models with additional vectorlike matter, but argue that a Type-I two Higgs doublet model provides a more economical scenario. In such a setup, going into regions of moderate-to-strong fermiophobia, the enhanced $$\gamma \gamma$$ branching ratio allows signals from $VH$+VBF production to yield $$\sigma \times BR_{\gamma\gamma} $$ comparable to total SM rates. Light $$H$$ production can be dominated via rare top decays $$t \rightarrow b H^+ \rightarrow b W^{*} H$$, which provides an alternate explanation of the excess. We consider this in the context of other Higgs anomalies, namely the LEP Higgs excess near the same mass, and excesses in $$t\bar{t}h$$ searches at Tevatron and LHC. We find that with $$140\, \mathrm{GeV} < m_{H^+} < 160\, \mathrm{GeV}$$, $$\tan \beta \sim 5$$ and a coupling to gauge bosons of $$\sin^2 \delta \sim 0.1$$, such a scenario can produce all the excesses simultanously, where $tth$ arise from contamination from the rare top decays, as previously proposed. An implication of the Type-I scenario is that any $$\gamma \gamma$$ excess should be associated with additional elements that could reduce background, including $$b$$-jets, forward jets or signs of vector boson production.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• Grant/Contract Number: AC02-07CH11359
• OSTI ID: 1463681
• Report Number(s): FERMILAB-PUB--17-468-T; arXiv:1710.07649; 1632004
• Journal Information: Journal of High Energy Physics (Online), Journal Name: Journal of High Energy Physics (Online) Journal Issue: 8 Vol. 2018; ISSN 1029-8479
• Publisher: Springer BerlinCopyright Statement
• Country of Publication: United States
• Language: English