Anomalous $Z'$ and Diboson Resonances at the LHC

TL;DR

This paper introduces new collider search strategies to detect light $Z'$ gauge bosons with mixed anomalies, focusing on exotic $Z$ decays and $Z'$ decays into electroweak bosons, enhancing LHC sensitivity.

Contribution

It proposes novel search methods leveraging Chern-Simons couplings for detecting anomalous $Z'$ bosons through exotic decay channels at the LHC.

Findings

Potential to probe $Z' o EW$ decays with lepton jet searches

Exotic $Z$ decay into $Z'\gamma$ is challenging for heavy $Z'$

Light $Z'$ can be effectively searched for via associated photon and lepton jets

Abstract

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 $Z'\gamma$ if the new gauge boson is sufficiently light, as well as $Z'$ decays into EW gauge bosons.While the exotic decay rate of the heavy $Z$ into $Z'\gamma$ is too small to be observed at the LHC, for a light $Z'$, we show the potential of a lepton jet search in association with a photon to probe the rare decay $Z \to Z' \gamma$.