Search for a dark vector gauge boson decaying to ${\pi }^{+}{\pi }^{-}$ using $\eta \to {\pi }^{+}{\pi }^{-}\gamma$ decays

E. Won, I. Adachi, H. Aihara +159

We report a search for a dark vector gauge boson $U^{\prime }$ that couples to quarks in the decay chain $D^{\ast +}\to D^0{\pi }^{+},D^0\to K_S^0\eta ,\eta \to U^{\prime }\gamma$, $U^{\prime }\to {\pi }^{+}{\pi }^{-}$…