Probing exotic Higgs sectors from the precise measurement of Higgs boson couplings

We study coupling constants of the standard model-like Higgs boson with the gauge bosons $hZZ$ and $hWW$ and fermions $hf\overline{f}$ in the general Higgs sector which contains higher isospin representations with arbitrary hypercharge. In the Higgs sectors with exotic Higgs representations, the $hZZ$ and $hWW$ coupling constants can be larger than those in the standard model. We calculate deviations in the Higgs boson couplings from standard model values in the model with a real or complex triplet field, the Georgi-Machacek model and the model with a septet scalar field. We also study deviations in the event rates of $h\ensuremath{\rightarrow}Z{Z}^{*}$, $h\ensuremath{\rightarrow}W{W}^{*}$, $h\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$, $h\ensuremath{\rightarrow}b\overline{b}$ and $h\ensuremath{\rightarrow}\ensuremath{\tau}\ensuremath{\tau}$ channels.