Extracting strong phase and $CP$ violation in $D$ decays by using quantum correlations in $\psi(3770)\to D^0 \overline{D}^0 \to (V_1V_2)(K \pi)$ and $\psi(3770)\to D^0\overline{D}^0\to (V_1V_2)(V_3V_4)

Abstract

We exploit the angular and quantum correlations in the $D\bar{D}$ pairs produced through the decay of the $\psi(3770)$ resonance in a charm factory to investigate CP-violation in two different ways. We consider the case of $\psi(3770)\rightarrow D\bar{D}\rightarrow (V_1V_2)(K\pi)$ decays, which provide a new way to measure the strong phase difference $\delta$ between Cabibbo-favored and doubly-Cabibbo suppressed $D$ decays required in the determination of the CKM angle $\gamma$. We also build CP-violating observables in $\psi(3770)\rightarrow D\bar{D}\rightarrow (V_1V_2)(V_3 V_4)$ to isolate specific new physics effects in the charm sector. Neglecting the systematics, we give a first rough estimate of the sensitivities of these measurements at BES-III with an integrated luminosity of 20 fb$^{-1}$ at $\psi(3770)$ peak and at a future super $\tau$-charm factory with a luminosity of $10^{35}$ cm$^{-2}$s$^{-1}$