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

TL;DR

This paper reports a measurement of time-dependent CP asymmetries and the CP-odd fraction in B0 --> D*+D*- decays, providing experimental values that test Standard Model predictions related to CP violation.

Contribution

It provides the first measurement of the CP-odd fraction and time-dependent CP asymmetries in B0 --> D*+D*- decays using a large data sample from BABAR.

Findings

CP-odd fraction measured as 0.063 +/- 0.055(stat) +/- 0.009(syst)

Time-dependent CP asymmetry parameter $Im(\lambda_+)$ is 0.05 +/- 0.29(stat) +/- 0.10(syst)

Parameter $|\lambda_+|$ is 0.75 +/- 0.19(stat) +/- 0.02(syst)

Abstract

We present a measurement of time-dependent CP asymmetries and an updated determination of the CP-odd fraction in the decay B0 --> D*+D*- using a data sample of 88 x 10^6 BBbar pairs collected by the BABAR detector at the PEP-II B Factory at SLAC. We determine the CP-odd fraction to be 0.063 +/- 0.055(stat) +/- 0.009(syst). The time-dependent CP asymmetry parameters $Im(\lambda_+)$ and $|\lambda_+|$ are determined to be 0.05 +/- 0.29(stat) +/- 0.10(syst) and 0.75 +/- 0.19(stat) +/- 0.02(syst), respectively. The Standard Model predicts these parameters to be -sin2beta and 1, respectively, in the absence of penguin diagram contributions.