Abstract
In this paper, we investigate the Higgs Triplet Model with hypercharge YΔ=0 (HTM0), an extension of the Standard model, caracterized by a more involved scalar spectrum consisting of two CP even Higgs h0,H0 and two charged Higgs bosons H±. We first show that the parameter space of HTM0, usually delimited by combined constraints originating from unitarity and BFB as well as experimental limits from LEP and LHC, is severely reduced when the modified Veltman conditions at one loop are also imposed. Then, we perform an rigorous analysis of Higgs decays either when h0 is the SM-like or when the heaviest neutral Higgs H0 is identified to the observed 125 GeV Higgs boson at LHC. In these scenarios, we perform an extensive parameter scan, in the lower part of the scalar mass spectrum, with a particular focus on the Higgs to Higgs decay modes H0→h0h0,H±H∓ leading predominantly to invisible Higgs decays. Finally, we also study the scenario where h0,H0 are mass degenerate. We thus find that consistency with LHC signal strengths favours a light charged Higgs with a mass about 176–178 GeV. Our analysis shows that the diphoton Higgs decay mode and H→Zγ are not always positively correlated as claimed in a previous study. Anti-correlation is rather seen in the scenario where h is SM like, while correlation is sensitive to the sign of the potential parameter λ when H is identified to 125 GeV observed Higgs.