研究者情報 | 神奈川大学

オクノ　ショウジ Okuno Shoji 奥野　祥二所属神奈川大学情報学部システム数理学科職種助教
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 K_S⁰, ψ (2S)K_S⁰, χ_c1K_S⁰, η_cK_S⁰, J/ψ K_L⁰ 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.