ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2005, vol. 71, p. 1-12
Improved measurement of CP-violation parameters sin 2φ 1 and |λ|, B meson lifetimes, and B 0-B̄ 0 mixing parameter Δm d
We present a precise measurement of the standard model CP-violation parameter sin2φ 1, the direct CP violation parameter |λ|, the lifetimes of charged and neutral B mesons and their ratio, and the B 0-B̄ 0 mixing parameter Δm d based on a sample of 152 x 10 6 BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e +e - collider. One of two B mesons is fully reconstructed in a CP-eigenstate or a flavor-eigenstate decay channel. The flavor of the accompanying B meson is identified from its decay products. From the distributions of the time interval between the two B meson decay points, we obtain sin2φ 1 = 0.728 ± 0.056(stat) ± 0.023(syst), |λ| = 1.007 ± 0.041(stat) ± 0.033(syst), τ B0 = [1.534 ± 0.008(stat) ± 0.010(syst)] ps, τ B+ = [1.635 ± 0.011(stat) ± 0.011(syst)] ps, τ B+/ τ B0 = 1.066 ± 0.008(stat) ± 0.008(syst) and Δm d = [0.511 ± 0.005(stat) ± 0.006(syst) ps -1. The results for sin2φ 1 and |λ| are consistent with the standard model expectations. The significance of the observed deviation from unity in the lifetime ratio exceeds 5 standard deviations. © 2005 The American Physical Society.