Probing new U(1) gauge symmetries via exotic Z → Z′γ decays

A bstract New U(1) gauge theories involving Standard Model (SM) fermions typically require additional electroweak for anomaly cancellation. We study the non-decoupling properties of these new fermions, called anomalons, in Z − Z′ γ vertex function, reviewing connection between full model and effective Wess-Zumino operator. calculate exotic → Z′γ decay width B−L B models, where L denote SM baryon lepton number symmetries. For symmetry, each generation is free $$ {Z}_{BL}^{\prime}\gamma Z BL ′ γ entirely induced by intragenerational mass splittings. In contrast, existence two distinct sources chiral symmetry breaking enables a heavy, anomaly-free set to have an irreducible contribution {Z}_B^{\prime}\gamma B width. show that current LEP limits on are weaker than previously estimated, low-mass {Z}_B^{\prime } dijet resonance searches currently more constraining. present summary collider bounds projection TeraZ factory decay, emphasize how emblematic anomalous