We revisit the neutral Higgs sector of the Higgs triplet model, with non-negligible mixing in the $CP$-even Higgs sector. We examine the possibility that one of the Higgs boson states is the particle observed at the LHC at 125 GeV, and the other is either the small LEP excess at 98 GeV, or the CMS excess at 136 GeV, or that the neutral Higgs bosons are (almost) degenerate and have both mass 125 GeV. We show that, under general considerations, an (unmixed) neutral Higgs boson cannot have an enhanced decay branching ratio into $\gamma \gamma$ with respect to the Standard Model one. An enhancement is, however, possible for the mixed case but only for the heavier of the two neutral Higgs bosons and not for mass-degenerate Higgs bosons. At the same time the branching ratios into $W{W}^{*}$, $Z{Z}^{*}$, $b\overline{b}$, and ${\tau }^{+}{\tau }^{-}$ are similar to the Standard Model, or reduced. We correlate the branching ratios of both Higgs states into $Z\gamma$ to those into $\gamma \gamma$ for the three scenarios. The mixed neutral sector of the Higgs triplet model exhibits some features that could distinguish it from other scenarios at the LHC.

• Received 3 December 2012

DOI:https://doi.org/10.1103/PhysRevD.87.015020