Evidence of Spin-Interference Effects in Exclusive $J/\psi \to e^{+}{e}^{-}$ Photoproduction in Ultraperipheral Heavy-Ion Collisions

The STAR Collaboration

We report the first evidence of spin interference in exclusive $J/\psi \to e^{+}{e}^{-}$ photoproduction in ultraperipheral heavy-ion collisions at STAR at $\sqrt{s_{NN}}=200$~GeV. In Au+A…