Improved measurement of time-dependentCPasymmetries and theCP-odd fraction in the decayB0→D*+D*−

Abstract

We present an updated measurement of the CP-odd fraction and the time-dependent CP asymmetries in the decay B0->D*+D*-using (383 +/- 4) \times 10^{6} BB pairs collected with the Babar detector. We determine the CP-odd fraction to be $0.143\pm0.034\stat\pm0.008\syst$. The time-dependent CP asymmetry parameters are determined to be $C_+ = -0.05\pm 0.14\stat \pm 0.02\syst$ and $S_+ = -0.72 \pm 0.19\stat \pm 0.05\syst$. The non-zero value of the measured $S_+$ indicates the evidence of CP violation at the $3.7 \sigma$ confidence level.