Measurement of sin 2β from B→J/ψK_s⁰ with the CDF detector

Authors

T. Affolder, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Collider Detector at Fermilab Collaboration

Date of this Version

4-1-2000

Comments

Published by American Physical Society. Phys. Rev. D 61, 072005 (2000). http://prd.aps.org. Copyright © 2000 American Physical Society. Permission to use.

Abstract

This paper reports an updated measurement of the standard model CP violation parameter sin 2β using the CDF Detector at Fermilab. The entire run I data sample of 110 pb^-1 of proton-antiproton collisions at √s =1.8 TeV is used to identify a signal sample of ≈400 B→J/ ψK_s⁰ events, where J/ψ→ μ⁺μ^- and K_s⁰→ π⁺ π^-. The flavor of the neutral B meson is identified at the time of production by combining information from three tagging algorithms: a same-side tag, a jet-charge tag, and a soft-lepton tag. A maximum likelihood fitting method is used to determine sin 2 β =0.79_-0.44^+0.41 (stat+syst). This value of sin 2 β is consistent with the standard model prediction, based upon existing measurements, of a large positive CP-violating asymmetry in this decay mode.