Light Z' signatures at the LHC

In this work, we discuss a distinctive pp -> Higgs -> Z'Z' -> 4l (l = e, mu) signal at the LHC, where the Higgs label refers to the Standard Model-like Higgs state discovered in 2012 or a lighter one in the framework of a theoretical model embedding a spontaneously broken U(1)' symmetry in addition to the Standard Model gauge group. The additional U(1)' symmetry generates a very light Z' state, with both vector and axial (nonuniversal) couplings to fermions, which are able to explain the so-called Atomki anomaly, compliant with current measurements of the anomalous magnetic moments of electron and muon as well as beam dump experiments. We show that the cross section for this process should be sufficiently large to afford one with significant sensitivity during run 3 of the LHC.

Automated summary

In this work, we analyze a specific pp -> Higgs -> Z'Z' -> 4l (l = e, mu) signal at the LHC, where the Higgs state can be either the Standard Model-like one discovered in 2012 or a lighter state in a theoretical model with a spontaneously broken U(1)' symmetry. The additional U(1)' symmetry introduces a very light Z' state, with vector and axial (nonuniversal) fermion couplings, providing an explanation for the Atomki anomaly and consistent with experimental measurements of the anomalous magnetic moments of electron and muon, as well as beam dump experiments. We demonstrate that the cross section for this process should be large enough to be significantly observed during run 3 of the LHC.