arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1104.5590hep-exhep-ph
收藏

辐射B^0 -> K^0 γ衰变的首次观测及其随时间的CP破坏测量

First Observation of Radiative B^0 -> ϕK^0 γDecays and Measurements of Their Time-Dependent CP Violation

H. Sahoo, T. E. Browder

摘要:

我们利用KEKB非对称能量e^+e^-对撞机上Belle探测器在π(4S)共振下收集的772 x 10^6个B-棒对的数据样本,首次观测到了辐射衰变B^0 -> γ K^0 γ。我们观察到37+/-8个事件的信号,其显著性为5.4个标准差,包括系统不确定性。测得的分支分数是${\cal B}(B^0 -> ϕK^0 γ) = (2.74\pm 0.60 \pm 0.32) \times 10^{-6}$,其中的不确定性分别是统计和系统的。我们还报告了第一次测量的时间相关的CP破坏参数:${\mathcal S}_{ϕK_S^0 γ} = +0.74^{+0.72}_{-1.05} (stat)^{+0.10}_{-0.24} (syst)$和${\mathcal A}_{ϕK_S^0 γ} = +0.35 +/- 0.58 (stat)^{+0.23}_{-0.10} (syst)$。进一步测量了${\mathcal B}(B^+ -> ϕK^+ γ) = (2.48 +/- 0.30 +/- 0.24) x 10^{-6}$、${\mathcal A}_{CP} = -0.03 +/- 0.11 +/- 0.08$,发现信号集中在阈值附近的M_{ϕK}质量区。

英文摘要:

We report the first observation of the radiative decay B^0 -> ϕK^0 γusing a data sample of 772 x 10^6 B B-bar pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We observe a signal of 37+/-8 events with a significance of 5.4 standard deviations including systematic uncertainties. The measured branching fraction is ${\cal B}(B^0 -> ϕK^0 γ) = (2.74\pm 0.60 \pm 0.32) \times 10^{-6}$, where the uncertainties are statistical and systematic, respectively. We also report the first measurements of time-dependent CP violation parameters: ${\mathcal S}_{ϕK_S^0 γ} = +0.74^{+0.72}_{-1.05} (stat)^{+0.10}_{-0.24} (syst)$ and ${\mathcal A}_{ϕK_S^0 γ} = +0.35 +/- 0.58 (stat)^{+0.23}_{-0.10} (syst)$. Furthermore, we measure ${\mathcal B}(B^+ -> ϕK^+ γ) = (2.48 +/- 0.30 +/- 0.24) x 10^{-6}$, ${\mathcal A}_{CP} = -0.03 +/- 0.11 +/- 0.08$ and find that the signal is concentrated in the M_{ϕK} mass region near threshold.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑