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arXiv 1702.07537hep-ph
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重-轻介子衰变常数中强同位旋破缺的局域对偶QCD求和规则

Local-duality QCD sum rules for strong isospin breaking in the decay constants of heavy-light mesons

Wolfgang Lucha, Dmitri Melikhov, Silvano Simula

备注：
14 pages. Typo corrected: the term describing power corrections in Eq.(1.1), which was lost when updating v2 -> v3, is restored. Notice that this term is also lost in the EPJC version (to be corrected via Erratum)
发表信息：
Eur. Phys. J. C78, 168 (2018)
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摘要：

在无限大Borel质量参数的局域对偶（LD）极限下，利用Borel QCD求和规则讨论了轻重介子的轻子衰变常数.在这个极限下，适当选择QCD关联函数中的不变结构，所有的真空凝聚贡献都消失了，所有的非微扰效应只包含在一个量中，即有效阈值。研究了大质量重夸克$m_Q$和小质量轻夸克$m_q$极限下LD有效阈值的性质。在重夸克极限下，我们阐明了辐射修正在再现赝标和矢量介子衰变常数的pQCD展开的有效阈值中所起的作用。我们表明介子衰变常数对$m_q$的依赖性主要（在70- 80%的水平上）来自于可计算的微扰谱密度的$m_q$依赖性。利用非奇异和奇异赝标及矢量重介子衰变常数的格点量子色动力学结果，我们得到了从几MeV到100 MeV范围内重轻介子衰变常数随$m_q$的变化的固体预言，并计算了相应的强同位旋破缺效应：$f_{D^+} - f_{D^0}=(0.96 \pm 0.09) ~ {\rm MeV}$，$f_{D^{*+}} - f_{D^{*0}}= (1.18 \pm 0.35) ~ {\rm MeV}$，$f_{B^0} - f_{B^+}=(1.01 \pm 0.10) ~ {\rm MeV}$，$f_{B^{*0}} - f_{B^{*+}}=(0.89 \pm 0.30) ~ {\rm MeV}$ .

英文摘要：

We discuss the leptonic decay constants of heavy--light mesons by means of Borel QCD sum~rules in the local-duality (LD) limit of infinitely large Borel mass parameter. In this limit, for an appropriate choice of the invariant structures in the QCD correlation functions, all vacuum-condensate contributions vanish and all nonperturbative effects are contained in only one quantity, the effective threshold. We study properties of the LD effective thresholds in the limits of large heavy-quark mass $m_Q$ and small light-quark mass $m_q$. In the heavy-quark limit, we clarify the role played by the radiative corrections in the effective threshold for reproducing the pQCD expansion of the decay constants of pseudoscalar and vector mesons. We show that the dependence of the meson decay constants on $m_q$ arises predominantly (at the level of 70--80%) from the calculable $m_q$-dependence of the perturbative spectral densities. Making use of the lattice QCD results for the decay constants of nonstrange and strange pseudoscalar and vector heavy mesons, we obtain solid predictions for the decay constants of heavy--light mesons as functions of $m_q$ in the range from a few to 100 MeV and evaluate the corresponding strong isospin-breaking effects: $f_{D^+} - f_{D^0}=(0.96 \pm 0.09) ~ {\rm MeV}$, $f_{D^{*+}} - f_{D^{*0}}= (1.18 \pm 0.35) ~ {\rm MeV}$, $f_{B^0} - f_{B^+}=(1.01 \pm 0.10) ~ {\rm MeV}$, $f_{B^{*0}} - f_{B^{*+}}=(0.89 \pm 0.30) ~ {\rm MeV}$.

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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