CP Asymmetry Measurements in psi K0 and the CKM Paradigm

Abstract

Recent experimental observations of CP asymmetry in B0 -> psi K0 constitute the first significant signal of CP violation outside the neutral kaon system; thus they represent an important milestone to test the CKM paradigm. We, therefore, undertake a critical appraisal of the existing experimental and theoretical inputs used to deduce constraints on sin(2 beta) and other important parameters and thus find, in particular, sin(2 beta) > 0.50 at 95% CL which is completely compatible with the combined experimental result: sin(2 beta) = 0.46 +- 0.17, representing an important success of the CKM model of CP violation. Searches for new physics in B decays to psi+K0 like final states will require improved precision; we make some suggestions to facilitate these. We also present a global fit including the new CP asymmetry measurements in B->psi+K0 as an additional input yielding e.g. gamma =29-56 degrees, eta-bar = >.19-.36, rho-bar=.15-.37, Jcp=(1.8 - 3.0) X 10^(-5), $Br(K+ -> pi+ nu nu-bar)=(0.51 - 0.90) X 10^(-10) and Br(KL -> pi0 nu nu-bar) = (0.11 - 0.31) X 10^(-10) at 95% CL.

Comments: 20 pages, 5 figures: In this version, which is to appear in Phys. Lett. B, we have: 1) corrected a minor error in the fitting algorithm which lowers the lower bound on rho-bar somewhat, 2) deleted figure 4(b) to save space and in figures 1(a), 4 and 5 we have included the 2-sigma (theory) error on x_i in displaying the Bs oscillation bound, 3) also added a short paragraph on page 5 comparing our results to those in the 2000 Particle Data Book article by Gilman et. al. and a footnote (#28) concerning the comparison with the scaning method of Ref 16