We propose novel collider searches which can significantly improve the LHC reach to new gauge bosons Z′ with mixed anomalies with the electroweak (EW) gauge group. Such a Z′ necessarily acquires a Chern-Simons coupling to the EW gauge bosons and these couplings can drive both exotic Z decays into Z′γ if the new gauge boson is sufficiently light, as well as Z′ decays into EW gauge bosons. For a light Z′, we show the potential of a lepton jet search in association with a photon to probe the rare decay Z→Z′γ. For a heavy leptophobic Z′, the exotic decay into EW gauge bosons is the only guaranteed non-hadronic decay mode, and can serve as an indispensable check of dijet resonance searches.
Tuesday, December 5, 2017