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arXiv 0907.2842hep-phhep-ex
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从QCD光锥求和规则得到半轻子粲衰变$D \to πl ν_ł$和$D \to K l ν_l$

Semileptonic charm decays $D \to πl ν_ł$ and $D \to K l ν_l$ from QCD Light-Cone Sum Rules

A. Khodjamirian, Ch. Klein, Th. Mannel, N. Offen

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34 pages, 5 figures
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摘要：

本文从QCD光锥求和规则出发，给出了$D\toπ$和$D \to K$形状因子的一种新的计算方法。对$c$ -夸克质量采用了$\overline{MS}$方案，并对输入参数进行了更新.结果为$f^+_{Dπ}(0)= 0.67^{+0.10}_{-0.07}$、$f^+_{DK}(0)=0.75^{+0.11}_{-0.08}$和$f^+_{Dπ}(0)/f^+_{DK}(0)=0.88 \pm 0.05$。结合最新的CLEO数据计算的形状因子，我们得到$|V_{cd}|=0.225\pm 0.005 \pm 0.003 ^{+0.016}_{-0.012}$和$|V_{cd}|/|V_{cs}|= 0.236\pm 0.006\pm 0.003\pm 0.013$的第一和第二个错误是实验的起源和第三个错误是由于我们的计算估计的不确定性。我们还评估了形状因子$f^-_{Dπ}$和$f^-_{DK}$，并预测$q^2=0$的斜率参数。此外，从$q^2<0$的求和规则计算形状因子，我们将它们拟合到各种参数化。经过解析延拓，再现了整个半轻子区$D\to π,K $形状因子的形状，与实验符合得很好。

英文摘要：

We present a new calculation of the $D\toπ$ and $D \to K$ form factors from QCD light-cone sum rules. The $\overline{MS}$ scheme for the $c$-quark mass is used and the input parameters are updated. The results are $f^+_{Dπ}(0)= 0.67^{+0.10}_{-0.07}$, $f^+_{DK}(0)=0.75^{+0.11}_{-0.08}$ and $f^+_{Dπ}(0)/f^+_{DK}(0)=0.88 \pm 0.05$. Combining the calculated form factors with the latest CLEO data, we obtain $|V_{cd}|=0.225\pm 0.005 \pm 0.003 ^{+0.016}_{-0.012}$ and $|V_{cd}|/|V_{cs}|= 0.236\pm 0.006\pm 0.003\pm 0.013$ where the first and second errors are of experimental origin and the third error is due to the estimated uncertainties of our calculation. We also evaluate the form factors $f^-_{Dπ}$ and $f^-_{DK}$ and predict the slope parameters at $q^2=0$. Furthermore, calculating the form factors from the sum rules at $q^2<0$, we fit them to various parameterizations. After analytic continuation, the shape of the $D\to π,K $ form factors in the whole semileptonic region is reproduced, in a good agreement with experiment.

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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