Triple $Z'$ signatures at $Z$ factories
Triple $Z'$ signatures at $Z$ factories
We discuss triple $Z'$ boson signatures via the decay chain of $Z \to Z' \phi \to Z' Z' Z'$, with a new light scalar $\phi$, at future Z factories such as CEPC and FCC-ee. These new bosons $\phi$ and $Z'$ naturally appear in models with a new $U(1)$ gauge symmetry …