LHC diphoton and Z+photon Higgs signals in the Higgs triplet model with Y=0

Abstract: We study the implications of the LHC diphoton and Z+photon Higgs signals on the Higgs triplet model with Y=0. We discuss three different scenarios: (i) the observed boson is the light Higgs boson $h$; (ii) it is the heavy Higgs boson $H$; (iii) the observed signal is from the almost degenerate $h$ and $H$. We find that the inclusive Higgs diphoton rates in the first two scenarios can be enhanced or suppressed compared to the SM value, which can respectively fit the ATLAS and CMS diphoton data within $1\sigma$ range. The inclusive $ZZ^*$ rates are suppressed, which are outside $1\sigma$ range of ATLAS data and within $1\sigma$ range of CMS data. Meanwhile, another CP-even Higgs boson production rate can be suppressed enough not to be observed at the collider. For the third scenario, the Higgs diphoton rate is suppressed, which is outside $1\sigma$ range of ATLAS data, and the $ZZ^*$ rate equals to SM value approximately. In addition, we find that the two rates of $h\to \gamma\gamma$ and $h\to Z\gamma$ have the positive correlations for the three scenarios.