Searching for a new leptophilic vector boson Z' with four-muon final state in the ATLAS detector

The talk presents a search for a new leptophilic vector boson Z' decaying into the four-muon final state using the data collected in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector in the year 2015-2018. A moderate excess of 4μ events with a μ+μ− pair is the experimental signature for this study. The gauge boson Z' is predicted by the highly motivated gauged Lμ−Lτ model, which is the simplest extension of the Standard Model (SM). The model addresses the observed g-2 of the muon anomalous magnetic dipole moment and the B physics anomalies. At the same time, the model probes physics and cosmology outstanding questions related to the dark matter and neutrino mass.