Measurement ofCP-Violating Asymmetries inB0Decays toCP

Abstract

We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta = 0.34+/-0.20 (stat)+/-0.05 (syst).

Exploring flavor structure of supersymmetry breaking atBfactories

“…• CP asymmetry in the B → J/ψ K S decay and related modes observed in the B factory experiments [1,2].…”

“…Both the Belle experiment at KEK and the BaBar experiment at SLAC observed large CP violation in B → J/ψ K S and related modes. These observations are the first discovery of CP violation out of the kaon system [1,2].…”

Measurement of Branching Fractions and Search forCP-Violating Charge Asymmetries in Charmless Two-BodyBDecays into Pions and Kaons

“…In the Standard Model, all CPviolating phenomena are a consequence of a single complex phase in the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix [1]. Recently, the Belle and BABAR collaborations published results [2,3] on measurements of CP -violating asymmetries in B decays into final states containing charmonium, leading to constraints on the angle β of the CKM Unitarity Triangle. Measurements of the rates and charge asymmetries for B decays into the charmless final states ππ and Kπ can be used to constrain the angles α and γ [4] of the Unitarity Triangle.…”

CP violation in the B0 meson system with BaBar

“…There are several significant changes in this analysis [4] relative to the first BABAR sin 2β publication [5]. The B CP modes χ c1 K 0 S and J/ψK * 0 (K * 0 → K 0 S π 0 ) have been added.…”

“…The B lifetime and mixing frequency are fixed at τ B 0 = 1.548 ps and ∆M B 0 = 0.472h ps −1 respectively [7]. The value of sin 2β and the asymmetry in the ∆t distribution were hidden using a blind analysis method (as described in [5]) until the event selection was optimized and all other aspects of the present analysis were complete. Figure 2 shows the ∆t distributions and A CP as a function of ∆t overlaid with the likelihood fit results for the η f = −1 candidates.…”