Multi-Z' signatures of spontaneously broken local U(1)' symmetry

We discuss multi-Z' signatures coming from decays of Higgs bosons in models with a spontaneously broken U(1)' symmetry, which can be observed as "lepton jets" or multilepton final states depending on the mass range of new bosons. We consider anomaly-free U(1)' models without introducing new fermions except for right-handed neutrinos, in which the Higgs sector is composed of an isospin doublet and a singlet fields with zero and nonzero U(1)' charges, respectively. The multi-Z' signatures can then be obtained via the decays of the discovered (extra) Higgs boson h (%), i.e., h-* Z'Z', %-* Z'Z', and/or h-* %%-* 4Z' as far as kinematically allowed. We give the upper limit on the branching ratios of h into Z'Z' and 4Z' from the current experimental data in each model. We also show the deviation in the hhh coupling from the standard model prediction at one-loop level, and find that its amount is typically smaller than 1%.