| The BABAR experiment at the SLAC National Accelerator Laboratory provides an excellent environment to study CP violation in B decays. A measurement of time-dependent CP-violating asymmetry in neutral B decays to charmonium states, in particular B0, B¯ 0 → J/psi K0L , is presented here. J/psi K0L is the most compelling CP-even final state used to measure the Unitarity Triangle parameter sin2beta at BABAR. The measurements reported here use a data sample of (465 +/- 5) million Upsilon(4 S) → BB¯ decays collected with the BABAR detector at the PEP-II asymmetric energy e +e- storage operating at the SLAC National Accelerator Laboratory. The time-dependent CP asymmetry parameters measured for the B0 → J/psi K0L decay are: C = -0.033 +/- 0.050(stat) +/- 0.027(syst) and S = -0.694 +/- 0.061(stat) +/- 0.031(syst). These results are in good agreement with the Standard Model predictions. |
