Kinematic Control and Dephasing Dynamics of Quantum Resources in $e^{+}e^{-}\toτ^{+}τ^{-}$

We characterize several quantum resources carried by the spins of the $τ^{+}τ^{-}$ pair produced in $e^{+}e^{-}$ annihilation. At the Belle-II energy, $\sqrt{s}=10.579\,\mathrm{GeV}$, Bell nonlocality, steerability, entanglement of formation, and coherence are governed by the production angle and ar