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Abstract

In the search for new physics, models of extra U(1) symmetries provide a simple but versatile theoretical framework to attenuate shortcomings of the Standard Model (SM). In an effort to systematically survey the physical prospects of such theories, we study three different phenomenological aspects of extra U(1) symmetries. First, studying Flavor-Changing Neutral Currents (FCNC) mediated by an effective heavy Z' boson, we identify the most stringent constraints for all possible combinations of lepton and quark flavor violating couplings.In regions of parameter space where severe bounds from meson mixing are avoided, LHC resonance searches can provide the leading constraint. Such scenarios are able to explain the observed (g-2)_\mu and tau decay anomalies. Second, we consider the possibility that the hidden photon is the gauge boson of the anomaly-free groups U(1)_{B-L}, U(1)_{L_\mu-L_e}, U(1)_{L_e-L_\tau} or U(1)_{L_\mu-L_\tau}. Taking into account loop-induced kinetic mixing, we perform a comprehensive analysis of all hidden photon constraints in these scenarios. While generically stringent bounds arise due to neutrino couplings, for U(1)_{L_{\mu}-L_\tau} an explanation of the (g-2)_\mu anomaly is possible. Finally, extending the previously considered U(1)_{L_\mu-L_\tau} model by a vector-like fermion \chi, we find that the (g-2)_\mu anomaly and the dark matter relic abundance can be simultaneously explained.