B介子衰變至ΦΦK的分支比與電荷宇稱不對稱性之測量

Abstract

在此篇論文中,使用了日本國家高能加速器中心B介子工廠（KEKB）的Belle偵測器，由非對稱能量之正負電子對撞所獲得的 414 fb^{-1}實驗數據。從實驗數據中，藉由濾除背景訊號來分析稀有衰變 B → ΦΦK 之衰變機率與電荷及宇稱不守恆。 我們首度證實了 B^+ → ΦΦK^+ 此一衰變過程確實存在，並且也發現了 B^0 → ΦΦK^0 可能存在的證據。 其衰變分率分別為： ● B(B^+ → ΦΦK^+)= [3.18^{+0.60}_{-0.52}(統計誤差) ± 0.27(系統誤差)] × 10^{-6} ● B(B^0 → ΦΦK^0) = [2.31^{+1.00}_{-0.74}(統計誤差) ± 0.24(系統誤差)] × 10^{-6} 在考慮到統計誤差與系統誤差之後，其訊號的顯著性分別是 9.53 與 4.74 個標準差。 此外，我們也做了相關的含魅衰變模式之分析： ● B(η_c → ΦΦ) = (3.01^{+1.06}_{-1.02} ± 0.19) × 10^{-3} ● B(η_c → ΦK^+K^-) = (4.35^{+1.45}_{-1.44} ± 0.29) × 10^{-3} ● B(η_c → 2(K^+K^-)) = (2.62^{+0.93}_{-0.90} ± 0.18) × 10^{-3} ● B(J/Ψ → ΦK^+K^-) = (1.45^{+0.30}_{-0.27} ± 0.11) × 10^{-3} ● B(J/Ψ → 2(K^+K^-)) = (9.73^{+1.77}_{-1.61} ± 0.84) × 10^{-4} 且被測量到的η_c寬度為 25.17^{+7.72}_{-5.98} ± 0.32 MeV。

In this thesis, we present measurements of the branching fraction and CP asymmetry of rare B decay B → ΦΦK. These measurements are based on a 414 fb^{-1} data sample, which contains 447 × 10^6 B Bbar pairs, collected with the Belle detector at the KEKB asymmetric-engry e^+e^- (3.5 on 8 GeV) collider operating at the ?(4S) resonance. We observe the B^+ → ΦΦK^+ decay and report the evidence for B^0 → ΦΦK^0 decay. The branching fractions are measured to be: ● B(B^+ → ΦΦK^+)= [3.18^{+0.60}_{-0.52}(stat) ± 0.27(sys)] × 10^{-6} ● B(B^0 → ΦΦK^0) = [2.31^{+1.00}_{-0.74}(stat) ± 0.24(sys)] × 10^{-6} for a ΦΦ invariant mass below 2.85 GeV/c^2, with significances including systematic uncertainty of 9.53 and 4.74 standard deviations, respectively. In addition, we also study the charmonium decays, related to the ΦΦK. The measured branching ratios are: ● B(η_c → ΦΦ) = (3.01^{+1.06}_{-1.02} ± 0.19) × 10^{-3} ● B(η_c → ΦK^+K^-) = (4.35^{+1.45}_{-1.44} ± 0.29) × 10^{-3} ● B(η_c → 2(K^+K^-)) = (2.62^{+0.93}_{-0.90} ± 0.18) × 10^{-3} ● B(J/Ψ → ΦK^+K^-) = (1.45^{+0.30}_{-0.27} ± 0.11) × 10^{-3} ● B(J/Ψ → 2(K^+K^-)) = (9.73^{+1.77}_{-1.61} ± 0.84) × 10^{-4} The measured width of η_c is 25.17^{+7.72}_{-5.98} ± 0.32 MeV.