Measurement of Time-Dependent CP Asymmetries and the CP-Odd Fraction in the Decay B0->D*+D*-

Abstract

We present an updated measurement of time-dependent \CP asymmetries and the \CP-odd fraction in the decay $B^0 \to D^{*+}D^{*-}$ using $232 \times 10^{6} \BB$ pairs collected by the \babar detector at the PEP-II $B$ factory. We determine the \CP-odd fraction to be $0.125 \pm 0.044\stat \pm 0.007\syst$. The time-dependent \CP asymmetry parameters $C_+$ and $S_+$ are determined to be $0.06\pm 0.17\stat \pm 0.03\syst$ and $-0.75 \pm 0.25\stat \pm 0.03\syst$, respectively. The Standard Model predicts these parameters to be 0 and $-\stwob$, respectively, in the absence of penguin amplitude contributions.