文章基本信息

标题：Pseudoscalar meson decay constants fK, fD and fDs, from Nf = 2 twisted mass Lattice QCD
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作者：C. Tarantino ; B. BLOSSIER ; V. Lubicz 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2008
卷号：2008
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present the results of a lattice QCD calculation of the pseudoscalar meson decay constants fK, fD and fDs , performed with Nf = 2 dynamical fermions. The simulation is carried out with the tree-level improved Symanzik gauge action and with the twisted mass fermionic action at maximal twist. With respect to our previous study [1], here we have analysed data at three values of the lattice spacing (a ≃ 0.10fm,0.09fm,0.07fm) and performed the continuum limit, and we have included at a = 0.09fm data with a lighter quark mass (mp ≃ 260MeV) and a larger volume (L ≃ 2.7fm), thus having at each lattice spacing L ≥ 2.4fm and Mp L ≥ 3.6. Our result for the kaon decay constant is fK = (157.5±0.8|stat.±3.3|syst.)MeV and for the ratio fK/ fp = 1.205±0.006|stat.±0.025|syst., in good agreement with the other Nf = 2 and Nf = 2+1 lattice calculations. For the D and Ds meson decay constants we obtain fD =(205±7|stat.±7|syst.)MeV, in good agreement with the CLEO-c experimentalmeasurement and with other recent Nf = 2 and Nf = 2+1 lattice calculations, and fDs = (248±3|stat.±8|syst.)MeV that, instead, is 2.3s below the CLEO-c/BABAR experimental average, confirming the present tension between lattice calculations and experimental measurements.