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arXiv 0810.1657hep-ex
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衰变B ^0-> D^{*-} l^+ nu_l的形状因子的测量和CKM矩阵元的确定|V_{cb}|

Measurement of the form factors of the decay B^0 -> D^{*-} l^+ nu_l and determination of the CKM matrix element |V_{cb}|

The Belle Collaboration, I. Adachi

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18 pages, 7 figures
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摘要：

本文利用衰变$B^0\to D^{*-}\ell^+ν_\ell$确定Cabibbo-Kobayashi-Maskawa矩阵元$|V_{cb}|$。我们进行了联合测量这个数量和形状因子$ρ^2$，$R_1(1)$，$R_2(1)$，充分表征这种衰变的框架中的重夸克有效理论，根据140 FB $^{-1}$的百丽附近的$Υ(4S)$共振收集的数据。基于约69，000个重建的$B^0\to D^{*-}\ell^+ν_\ell$衰变，结果为$ρ^2=1.293\pm 0.045\pm 0.029$、$R_1(1)=1.495\pm 0.050\pm 0.062$、$R_2(1)=0.844\pm 0.034\pm 0.019$和$\mathcal{F}(1)|V_{cb}|=34.4\pm 0.2\pm 1.0$。发现$B^0\to D^{*-}\ell^+ν_\ell$支化级分为$(4.42\pm 0.03\pm 0.25)%$。对于所有这些数字，第一个误差是统计误差，第二个误差是系统不确定性。所有结果都是初步的。

英文摘要：

This paper describes a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ using the decay $B^0\to D^{*-}\ell^+ν_\ell$. We perform a combined measurement of this quantity and of the form factors $ρ^2$, $R_1(1)$, and $R_2(1)$ which fully characterize this decay in the framework of heavy-quark effective theory, based on 140 fb$^{-1}$ of Belle data collected near the $Υ(4S)$ resonance. The results, based on about 69,000 reconstructed $B^0\to D^{*-}\ell^+ν_\ell$ decays, are $ρ^2=1.293\pm 0.045\pm 0.029$, $R_1(1)=1.495\pm 0.050\pm 0.062$, $R_2(1)=0.844\pm 0.034\pm 0.019$ and $\mathcal{F}(1)|V_{cb}|=34.4\pm 0.2\pm 1.0$. The $B^0\to D^{*-}\ell^+ν_\ell$ branching fraction is found to be $(4.42\pm 0.03\pm 0.25)%$. For all these numbers, the first error is the statistical and the second is the systematic uncertainty. All results are preliminary.

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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