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arXiv 1609.05050hep-phhep-lat
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从QCD求和规则研究重介子衰变常数的同位旋破缺

Isospin breaking in the decay constants of heavy mesons from QCD sum rules

Wolfgang Lucha, Dmitri Melikhov, Silvano Simula

备注：
8 pages, 1 figure; this version matches the published one
发表信息：
Phys. Lett. B765 (2017) 365-370
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摘要：

本文用QCD求和定则方法研究了QCD中由于$u$ -和$d$ -夸克质量的不同而引起的强同位旋破缺效应对粲夸克和美夸克的轻子衰变常数的影响。本文应用求和规则分析了含一个重夸克和一个轻夸克的介子的衰变常数，其轻质量在平均$u/d$夸克质量到奇夸克质量的范围内。然后我们分析了衰变常数对轻夸克质量的依赖性，并以很好的精度提取了质量差$(m_d - m_u)$中首阶衰变常数的IB比，得到：$(f_{D^+} - f_{D^0}) / f_{D} = 0.0047 (6)$，$(f_{D^{*+}} - f_{D^{*0}}) / f_{D^*} = 0.0068 (9)$，$(f_{B^0} - f_{B^+}) / f_{B} = 0.0047 (6)$，和$(f_{B^{*0}} - f_{B^{*+}}) / f_{B^*} = 0.0045 (5)$，从而产生：$f_{D^+} - f_{D^0} = 0.97 \pm 0.13$ MeV，$f_{D^{*+}} - f_{D^{*0}} = 1.73 \pm 0.27$ MeV，$f_{B^0} - f_{B^+} = 0.90 \pm 0.13$ MeV，$f_{B^{*0}} - f_{B^{*+}} = 0.81 \pm 0.11$ MeV。在$D$ -介子的情况下，我们的发现是一致的最近的晶格QCD结果，而它是低得多的$B$ -介子的情况下，显示出$\approx 3$标准偏差的张力。

英文摘要：

We present a study of the strong isospin-breaking (IB) effect, due in QCD to the difference between $u$- and $d$-quark masses, in the leptonic decay constants of charmed and beauty pseudoscalar and vector mesons using the method of QCD sum rules. We apply the sum-rule analysis to the decay constants of mesons containing one heavy quark and one light quark with the light mass in the range from the average $u/d$ quark mass to the strange-quark mass. We then analyse the dependence of the decay constants on the light quark mass and extract with good accuracy the IB ratios of decay constants at leading order in the mass difference $(m_d - m_u)$, obtaining: $(f_{D^+} - f_{D^0}) / f_{D} = 0.0047 (6)$, $(f_{D^{*+}} - f_{D^{*0}}) / f_{D^*} = 0.0068 (9)$, $(f_{B^0} - f_{B^+}) / f_{B} = 0.0047 (6)$, and $(f_{B^{*0}} - f_{B^{*+}}) / f_{B^*} = 0.0045 (5)$, which yield: $f_{D^+} - f_{D^0} = 0.97 \pm 0.13$ MeV, $f_{D^{*+}} - f_{D^{*0}} = 1.73 \pm 0.27$ MeV, $f_{B^0} - f_{B^+} = 0.90 \pm 0.13$ MeV, $f_{B^{*0}} - f_{B^{*+}} = 0.81 \pm 0.11$ MeV. In the case of the $D$-meson our finding is consistent with recent lattice QCD results, whereas it is much lower in the case of the $B$-meson showing a tension of $\approx 3$ standard deviations.

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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