Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland.
Phys Rev Lett. 2012 May 25;108(21):211803. doi: 10.1103/PhysRevLett.108.211803. Epub 2012 May 23.
We search for annihilation decay modes of neutral b mesons into pairs of charmless charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 6 fb(-1) of integrated luminosity, we obtain the first evidence for the B(s)(0)→π(+)π(-) decay, with a significance of 3.7σ, and a measured branching ratio B(B(s)(0)→π(+)π(-))=(0.57±0.15(stat)±0.10(syst))×10(-6). A search for the B(0)→K(+)K(-) mode in the same sample yields a significance of 2.0σ, and a central value estimate B(B(0)→K(+)K(-))=(0.23±0.10(stat)±0.10(syst))×10(-6).
我们使用费米实验室 Tevatron 上升级后的对撞机探测器,寻找中性 B 介子衰变为无粲荷电强子对的湮没衰变模式。利用对应于 6 fb(-1)积分亮度的数据集,我们首次观测到 B(s)(0)→π(+)π(-)衰变,置信度为 3.7σ,测量的分支比为 B(B(s)(0)→π(+)π(-))=(0.57±0.15(stat)±0.10(syst))×10(-6)。在同一数据集内,我们还搜索了 B(0)→K(+)K(-)模式,置信度为 2.0σ,中心值估计为 B(B(0)→K(+)K(-))=(0.23±0.10(stat)±0.10(syst))×10(-6)。