Measurement of Time-Dependent CP Asymmetries in B0 -> D(*)D Decays

TL;DR

This paper reports the first measurement of time-dependent CP asymmetries in B0 decays to D(*)D final states, providing insights into CP violation in the B meson system using data from the BABAR experiment.

Contribution

It presents the first measurement of CP asymmetries in B0 -> D+D- decays and updates measurements for B0 -> D*+D- and D*-D+ decays, using a large data sample from BABAR.

Findings

Measured CP asymmetry parameters with statistical and systematic uncertainties.

First observation of CP asymmetries in B0 -> D+D- decays.

Updated measurements for B0 -> D*+D- and D*-D+ decays.

Abstract

We present a first measurement of CP asymmetries in neutral B decays to D+D-, and updated CP asymmetry measurements in decays to D*+D- and D*-D+. We use fully-reconstructed decays collected in a data sample of (232 +- 3) x 10^6 Y(4S) -> BBbar events in the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine the time-dependent asymmetry parameters to be S_{D*+D-} = -0.54 +- 0.35 +- 0.07, C_{D*+D-} = 0.09 +- 0.25 +- 0.06, S_{D*-D+} = -0.29 +- 0.33 +- 0.07, C_{D*-D+} = 0.17 +- 0.24 +- 0.04, S_{D+D-} = -0.29 +- 0.63 +- 0.06, and C_{D+D-} = 0.11 +- 0.35 +- 0.06, where in each case the first error is statistical and the second error is systematic.