# Measurement of sin2$\beta$ in $B^0 \to \phi K^0_S$

Abstract : We present a preliminary measurement of the time-dependent CP-violating asymmetry in the neutral B decay B0 --> phi K0S, with phi --> K+K- and K0S --> pi+pi-. The measurement uses a data sample of about 87 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC. In this sample we study events in which the CP final state is fully reconstructed and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry sin2beta is derived from the decay-time distributions. We measure sin2beta = -0.19 +0.52-0.50 (stat) +/- 0.09 (syst) (preliminary).
Document type :
Conference papers

http://hal.in2p3.fr/in2p3-00012426
Contributor : Claudine Bombar <>
Submitted on : Tuesday, January 14, 2003 - 4:55:45 PM
Last modification on : Wednesday, January 6, 2021 - 6:22:02 PM

### Citation

B. Aubert, D. Boutigny, J.M. Gaillard, A. Hicheur, Y. Karyotakis, et al.. Measurement of sin2$\beta$ in $B^0 \to \phi K^0_S$. International Conference on High Energy Physics 31 ICHEP 2002, Jul 2002, Amsterdam, Netherlands. pp.1-15. ⟨in2p3-00012426⟩

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