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arXiv 0804.3908hep-ex
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在CDF上寻找B^+ -> mu^+ mu^- K^+、B^0 -> mu^+ mu^- K^*0(892)和B^0_s -> mu^+ mu^- phi的稀有衰变

Search for the Rare Decays B^+ -> mu^+ mu^- K^+, B^0 -> mu^+ mu^- K^*0(892), and B^0_s -> mu^+ mu^- phi at CDF

CDF Collaboration, T. Aaltonen

摘要:

我们用费米实验室Tevatron上的CDF II探测器收集到的能量为1.96 TeV、能量为924 pb ^{-1}的p巴碰撞的B介子(B^+、B^0或B^0_s)衰变中的b到sμ^+μ^-跃迁。我们发现,在B^+到μ^+μ^-K^+、B^0到μ^+ μ ^-K^*(892)^0和B_s^0到μ^+μ^-K^*(892)^0的衰变模式中,分别有4.5、2.9和2.4个标准差的显著性过剩。使用B至J/psi h(h = K^+,K^*(892)^0,phi)衰变作为归一化通道,我们报告了先前观察到的B^+和B^0衰变的分支分数,BR(B^+至μ^+μ^-K^+)=(0.59 \pm 0.15 \pm 0.04)x 10^{-6},和BR(B^0至μ^+μ^-K^*(892)^0)=(0.81 \pm 0.30 \pm 0.10)x 10^{-6},其中第一个不确定度是统计的,第二个是系统的。这些测量结果与世界平均结果一致,与现有最佳测量结果相比具有竞争力。我们将相对分支分数BR(B_s^0至μ^+μ^-λ)/BR(B_s^0至J/λ)的上限设定为<2.6(2.3)\times 10^{-3},置信水平为95(90)%,这是迄今为止最严格的。

英文摘要:

We search for b to sμ^+μ^- transitions in B meson (B^+, B^0, or B^0_s) decays with 924pb^{-1} of p pbar collisions at sqrt(s)=1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We find excesses with significances of 4.5, 2.9, and 2.4 standard deviations in the B^+ to μ^+μ^-K^+, B^0 to μ^+μ^-K^*(892)^0, and B_s^0 to μ^+μ^-ϕdecay modes, respectively. Using B to J/psi h (h = K^+, K^*(892)^0, phi) decays as normalization channels, we report branching fractions for the previously observed B^+ and B^0 decays, BR(B^+ to μ^+μ^-K^+)=(0.59\pm0.15\pm0.04) x 10^{-6}, and BR(B^0 to μ^+μ^-K^*(892)^0)=(0.81\pm0.30\pm0.10) x 10^{-6}, where the first uncertainty is statistical, and the second is systematic. These measurements are consistent with the world average results, and are competitive with the best available measurements. We set an upper limit on the relative branching fraction BR(B_s^0 to μ^+μ^-ϕ)/BR(B_s^0 to J/ψϕ) <2.6(2.3)\times10^{-3} at the 95(90)% confidence level, which is the most stringent to date.

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