Multi-$Z^{\prime }$ signatures of spontaneously broken local $U(1{)}^{\prime }$ symmetry

Abstract

We discuss multi-$Z^{\prime }$ signatures coming from decays of Higgs bosons in models with a spontaneously broken $U(1{)}^{\prime }$ symmetry, which can be observed as "lepton jets" or multi-lepton final states depending on the mass range of new bosons. We consider anomaly-free $U(1{)}^{\prime }$ 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 non-zero $U(1{)}^{\prime }$ charges, respectively. The multi-$Z^{\prime }$ signatures can then be obtained via the decays of the discovered (extra) Higgs boson $h$ ($\varphi$), i.e., $h\to Z^{\prime }{Z}^{\prime }$, $\varphi \to Z^{\prime }{Z}^{\prime }$ and/or $h\to \varphi \varphi \to 4Z^{\prime }$ as far as kinematically allowed. We give the upper limit on the branching ratios of $h$ into $Z^{\prime }{Z}^{\prime }$ and $4Z^{\prime }$ 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\%.

Comments: 26 pages, 4 figures