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arXiv 0809.4027hep-ex
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$B^+ \to \ell^+ ν_{\ell}$与$B^{-}\to D^{0} \ell^{-}\barν X$的比较研究

A Search for $B^+ \to \ell^+ ν_{\ell}$ Recoiling Against $B^{-}\to D^{0} \ell^{-}\barν X$

The BABAR Collaboration, B. Aubert

备注：
30 pages, 15 postscript figures, submitted to CKM2008
发表信息：
Phys.Rev.D81:051101,2010
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摘要：

我们提出了一个搜索的衰变$\B^+ \to \ell^+ ν_{\ell} (\ell = τ, μ, \mathrm{or} e)$在$(458.9 \pm 5.1) \times 10^{6}$ $Υ(4S)$衰变记录与巴巴尔探测器在SLAC PEP-II $B$ -工厂。选择具有一个重建的排他性半轻子B衰变（$B^{-}\to D^{0} \ell^{-}\barν X$）的事件的样本，并且在反冲中执行对$\B^+ \to \ell^+ ν_{\ell}$信号的搜索。$τ$在以下通道中识别：$τ^+ \to e^+ ν_e \overlineν_τ$、$τ^+ \to μ^+ ν_μ \overlineν_τ$、$τ^+ \to π^+ \overlineν_τ$和$τ^+ \to π^+ π^{0} \overlineν_τ$。建立了支化分数提取或上限测定的分析策略和统计方法。我们从数据集中确定了$\mathcal{B}(\B^+ \to τ^+ ν_τ) = (1.8 \pm 0.8 \pm 0.1) \times 10^{-4}$的初步测量值，其中不包括$2.4 σ$和$f_{B} = 230 \pm 57 \mev $处的零。与强子标记的测量结合产生$\mathcal{B}(\B^+ \to τ^+ ν_τ) = (1.8 \pm 0.6) \times 10^{-4}$。我们还对$\mathcal{B}(\B^+ \to e^+ ν_{e}) < 7.7 \times 10^{-6} (\textrm{90% C.L.})$、$\mathcal{B}(\B^+ \to μ^+ ν_μ) < 11 \times 10^{-6} (\textrm{90% C.L.})$和$\mathcal{B}(\B^+ \to τ^+ ν_τ) < 3.2 \times 10^{-4} (\textrm{90% C.L.})$的分支分数设定了初步限制。

英文摘要：

We present a search for the decay $\B^+ \to \ell^+ ν_{\ell} (\ell = τ, μ, \mathrm{or} e)$ in $(458.9 \pm 5.1) \times 10^{6}$ $Υ(4S)$ decays recorded with the Babar detector at the SLAC PEP-II $B$-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay ($B^{-}\to D^{0} \ell^{-}\barν X$) is selected, and in the recoil a search for $\B^+ \to \ell^+ ν_{\ell}$ signal is performed. The $τ$ is identified in the following channels: $τ^+ \to e^+ ν_e \overlineν_τ$, $τ^+ \to μ^+ ν_μ \overlineν_τ$, $τ^+ \to π^+ \overlineν_τ$, and $τ^+ \to π^+ π^{0} \overlineν_τ$. The analysis strategy and the statistical procedure is set up for the branching fraction extraction or upper limit determination. We determine from the dataset a preliminary measurement of $\mathcal{B}(\B^+ \to τ^+ ν_τ) = (1.8 \pm 0.8 \pm 0.1) \times 10^{-4}$, which excludes zero at $2.4 σ$, and $f_{B} = 230 \pm 57 \mev $. Combination with the hadronically tagged measurement yields $\mathcal{B}(\B^+ \to τ^+ ν_τ) = (1.8 \pm 0.6) \times 10^{-4}$. We also set preliminary limits on the branching fractions at $\mathcal{B}(\B^+ \to e^+ ν_{e}) < 7.7 \times 10^{-6} (\textrm{90% C.L.})$, $\mathcal{B}(\B^+ \to μ^+ ν_μ) < 11 \times 10^{-6} (\textrm{90% C.L.})$, and $\mathcal{B}(\B^+ \to τ^+ ν_τ) < 3.2 \times 10^{-4} (\textrm{90% C.L.})$.

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。

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