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

TL;DR

This paper reports an updated measurement of CP-odd fraction and time-dependent CP asymmetries in B0->D*+D*- decays, providing evidence of CP violation with improved precision using a large data sample.

Contribution

It provides the most recent measurement of CP-odd fraction and CP asymmetry parameters in B0->D*+D*- decays, with reduced uncertainties and evidence of CP violation.

Findings

CP-odd fraction measured as 0.143±0.034 (stat)±0.008 (syst)

CP asymmetry parameter S+ measured as -0.72±0.19 (stat)±0.05 (syst)

Evidence of CP violation at 3.7 sigma confidence level

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.