ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2005, vol. 94, p. -
Improved measurement of CP asymmetries in B0→(c̄c) K0(*) decays
We present results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 227 × 106 Y(4S) → BB̄ decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The amplitude of the CPasymmetry, sin2β in the standard model, is derived from decay-time distributions from events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0 from its decay products. We measure sir2β = 0.722 ±0.040(stat) ±0.023(syst) in agreement with the standard model expectation. © 2005 The American Physical Society.