Improved Measurement of the CP-Violating Asymmetry Amplitude sin2beta
- SLAC
We present updated results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 62 million {Upsilon}(4S) {yields} B{bar B} decays collected between 1999 and 2001 by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. In this sample we study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson 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 sin2{beta}, is derived from the decay time distributions in such events. We measure sin2{beta} = 0.75 {+-} 0.09 (stat) {+-} 0.04 (syst) and |lambda| = 0.92 {+-} 0.06 (stat) {+-} 0.02 (syst). The latter is consistent with the Standard Model expectation of no direct CP violation. These results are preliminary.
- Research Organization:
- Stanford Linear Accelerator Center, Menlo Park, CA (US)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 826714
- Report Number(s):
- SLAC-PUB-9153
- Country of Publication:
- United States
- Language:
- English
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