Improved Measurement of CP Asymmetries in $\Bz \to (\ccbar) K^{(*)0}$ Decays

TL;DR

This paper reports an improved measurement of CP asymmetries in neutral B meson decays to charmonium states, using a large data sample collected over several years, refining key parameters related to CP violation.

Contribution

The study provides updated, more precise measurements of sin2beta and || in B decays, enhancing the understanding of CP violation in the Standard Model.

Findings

Measured sin2beta = 0.710 1 0.034 (stat) 1 0.019 (syst)

Determined || = 0.932 1 0.026 (stat) 1 0.017 (syst)

Results are preliminary and improve previous measurements.

Abstract

We present an updated measurements of time-dependent CP asymmetries in fully reconstructed neutral B decays to several CP eigenstates containing a charmonium meson. The measurements use a data sample of (347.5 +/- 3.8) x 10^{6} $\FourS \to B\Bbar$ decays collected with the babar detector at the PEP-II B factory between 1999 and 2006. We determine sin2beta = 0.710 +/- 0.034(stat) +/- 0.019(syst) and |\lambda| = 0.932 +/- 0.026(stat) +/- 0.017(syst). Both of these results are preliminary.