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arXiv 0901.1216hep-ex
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4170 MeV附近600/pb e+e湮没数据B(Ds+ -->ell+ nu)和衰变常数fDs的测量

Measurement of B(Ds+ -->ell+ nu) and the Decay Constant fDs From 600/pb of e+e- Annihilation Data Near 4170 MeV

CLEO Collaboration, J. P. Alexander

摘要:

为了精确测量衰变常数fDs,我们用CLEO-c探测器研究了4170 MeV的e+e-> Ds^-Ds ^{*+}和Ds^{*-}Ds^{+}相互作用。以前,我们的测量大大高于最精确的晶格基QCD计算(241 +/- 3)MeV。这里我们使用D_s^+ --> ell^+ nu通道,其中ell^+表示mu^+或tau^+,而tau^+ --> pi^+表示反-nu。对两种模式分别进行分析,我们确定B(D_s^+ --> mu^+ nu)= 0.565 +/- 0.045 +/- 0.017)%,B(D_s^+ --> mu^+ nu)=(6.42 +/- 0.81 +/- 0.18)%。我们还同时分析了它们,得到了B^{eff}(D_s^+ --> mu^+ nu)=(0.591 +/- 0.037 +/- 0.018)%和fDs=(263.3 +/- 8.2 +/- 3.9)MeV的有效值。结合使用D_s^+ --> tau^+ nu,tau^+ --> e^+ nu anti-nu衰变独立测定的CLEO-c值,我们得到fDs=(259.5 +/- 6.6 +/- 3.1)MeV。结合我们先前对B(D^+ -> mu^+ nu)的测定,我们得出fDs/fD+=1.26 +/- 0.06 +/- 0.02。没有发现Gamma(D_s^+ --> mu^+ v)和Γ(D_s^-> mu^- nu)之间CP不对称的证据;具体地说,速率的分数差异测量为(4.8 +/- 6.1)%。最后,在90%的置信水平下,我们发现B(D_s^+ --> e^+ nu)<1.2 × 10 ^{-4}。

英文摘要:

We examine e+e- --> Ds^-D_s^{*+} and Ds^{*-}Ds^{+} interactions at 4170 MeV using the CLEO-c detector in order to measure the decay constant fDs with good precision. Previously our measurements were substantially higher than the most precise lattice based QCD calculation of (241 +/- 3) MeV. Here we use the D_s^+ --> ell^+ nu channel, where the ell^+ designates either a mu^+ or a tau^+, when the tau^+ --> pi^+ anti-nu. Analyzing both modes independently, we determine B(D_s^+ --> mu^+ nu)= 0.565 +/- 0.045 +/- 0.017)%, and B(D_s^+ --> mu^+ nu)= (6.42 +/- 0.81 +/- 0.18)%. We also analyze them simultaneously to find an effective value of B^{eff}(D_s^+ --> mu^+ nu)= (0.591 +/- 0.037 +/- 0.018)% and fDs=(263.3 +/- 8.2 +/- 3.9) MeV. Combining with the CLEO-c value determined independently using D_s^+ --> tau^+ nu, tau^+ --> e^+ nu anti-nu decays, we extract fDs=(259.5 +/- 6.6 +/- 3.1) MeV. Combining with our previous determination of B(D^+ --> mu^+ nu), we extract the ratio fDs/fD+=1.26 +/- 0.06 +/- 0.02. No evidence is found for a CP asymmetry between Gamma(D_s^+ --> mu^+ν) and Γ(D_s^- --> mu^- nu); specifically the fractional difference in rates is measured to be (4.8 +/- 6.1)%. Finally, we find B(D_s^+ --> e^+ nu) < 1.2x10^{-4} at 90% confidence level.

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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