オクノ ショウジ   Okuno Shoji
  奥野 祥二
   所属   神奈川大学  工学部 情報システム創成学科
   職種   助教
言語種別 日本語
発行・発表の年月 2002/08
形態種別 学術雑誌
標題 Observation of mixing-induced CP violation in the neutral B meson system
執筆形態 共著
掲載誌名 Phys. Rev. D 66, 032007 (2002) (22 pages)
概要 K. Abe, S. Okuno, et al. [Belle Collaboration]
, This article describes an observation of mixing-induced CP violation and a measurement of the CP violation parameter, §in 2φ1, with the Belle detector at the KEKB asymmetric e+e- collider. Using a data sample of 29.1fb-1 recorded on the υ(4S) resonance that contains 31.3 million B{B} pairs, we reconstruct decays of neutral B mesons to the following CP eigenstates: J/ψ KS0, ψ (2S)KS0, χc1KS0, ηcKS0, J/ψ KL0 and J/ψ K*0. The flavor of the accompanying B meson is identified by combining information from primary and secondary leptons, K± mesons, Λ baryons, slow and fast pions. The proper-time interval between the two B meson decays is determined from the distance between the two decay vertices measured with a silicon vertex detector. The result sin 2φ1 = 0.99±0.14 (stat)±0.06 (syst) is obtained by applying a maximum likelihood fit to the 1137 candidate events. We conclude that there is large CP violation in the neutral B meson system. A zero value for §in 2φ1 is ruled out by more than six standard deviations.