Leptonic decay constants fK, fD and fDs with Nf = 2+1+1 twisted-mass lattice QCD
Leptonic decay constants fK, fD and fDs with Nf = 2+1+1 twisted-mass lattice QCD
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DOI：
10.1103/physrevd.91.054507
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发表时间：
2014-11
影响因子：
5
通讯作者：
N. Carrasco;P. Dimopoulos;R. Frezzotti;P. Lami;V. Lubicz;F. Nazzaro;E. Picca;L. Riggio;G. Ro
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作者：
N. Carrasco;P. Dimopoulos;R. Frezzotti;P. Lami;V. Lubicz;F. Nazzaro;E. Picca;L. Riggio;G. Ro
本文用格点QCD方法计算了赝标衰变常数fK、fD和fDs，用的规范位形是由欧洲扭曲质量合作组产生的Nf = 2 + 1 + 1的动力学夸克，在海中除了两个轻质量简并夸克外，还包括质量接近于真实的世界质量的奇异夸克和魅夸克。模拟是基于一个单一的设置为两个轻质量简并夸克和一个混合行动的方法为奇怪和魅力夸克。我们使用的数据模拟在三个不同的值的晶格间距在0.06 - 0.09 FM的范围内，并在π介子质量在210 - 450兆电子伏的范围内。我们的主要结果是：fK+ / fpi+ = 1.184（16），fK+ = 154.4（2.0）MeV，其中包含了由于上夸克和下夸克质量差引起的领先的强同位旋破缺修正，fK = 155.0（1.9）MeV，fD = 207.4（3.8）MeV，fDs = 247.2（4.1）MeV，fDs / fD = 1.192（22），（fDs / fD）/（fK / fpi）= 1.003（14）。结合K介子、π介子、D介子和Ds介子轻子衰变率的实验测量，我们的结果导致CKM矩阵元的如下确定：|VUS| = 0.2269（29），|VCD| = 0.2221（67）和|VCs| = 1.014（24）。使用的最新值|VUD|从超允许的核β衰变中，CKM矩阵的第一行的么正性在permille水平上得到满足。
We present a lattice QCD calculation of the pseudoscalar decay constants fK, fD and fDs performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their values in the real world. The simulations are based on a unitary setup for the two light mass-degenerate quarks and on a mixed action approach for the strange and charm quarks. We use data simulated at three different values of the lattice spacing in the range 0.06 - 0.09 fm and at pion masses in the range 210 - 450 MeV. Our main results are: fK+ / fpi+ = 1.184 (16), fK+ = 154.4 (2.0) MeV, which incorporate the leading strong isospin breaking correction due to the up- and down-quark mass difference, and fK = 155.0 (1.9) MeV, fD = 207.4 (3.8) MeV, fDs = 247.2 (4.1) MeV, fDs / fD = 1.192 (22) and (fDs / fD) / (fK / fpi) = 1.003 (14) obtained in the isospin symmetric limit of QCD. Combined with the experimental measurements of the leptonic decay rates of kaon, pion, D- and Ds-mesons our results lead to the following determination of the CKM matrix elements: |Vus| = 0.2269 (29), |Vcd| = 0.2221 (67) and |Vcs| = 1.014 (24). Using the latest value of |Vud| from superallowed nuclear beta decays the unitarity of the first row of the CKM matrix is fulfilled at the permille level.