Study of CP Violating Effects in Time Dependent $B^0(\bar{B^0}) \to D^{(*)\mp}π^{\pm}$ Decays

Abstract

We report measurements of time dependent decay rates for $B^0(\bar{B}^0) \to D^{(*)\mp}π^{\pm}$ decays and extraction of CP violation parameters containing $ϕ_3$. Using fully reconstructed $D^{(*)}π$ events from a $140 {\rm fb}^{-1}$ data sample collected at the $Υ(4S)$ resonance, we obtain the CP violation parameters for $D^* π$ and $D π$ decays, $2R_{D^{(*)} π} \sin (2ϕ_1 + ϕ_3 \pm δ_{D^{(*)} π})$, where $R_{D^{(*)} π}$ is the ratio of the magnitudes of the doubly-Cabibbo-suppressed and Cabibbo-favoured amplitudes, and $δ_{D^{(*)} π}$ is the strong phase difference between them. Under the assumption of $δ_{D^{(*)} π}$ being close to either 0 or $180^{\circ}$, we obtain $|2R_{D^* π} \sin (2ϕ_1 + ϕ_3)| = 0.060 \pm 0.040(\mathrm{stat}) \pm 0.019(\mathrm{sys})$ and $|2R_{D π} \sin (2ϕ_1 + ϕ_3)| = 0.061 \pm 0.037(\mathrm{stat}) \pm 0.018(\mathrm{sys})$.