Charmed and light pseudoscalar meson decay constants from HISQ simulations

Fermilab Lattice and MILC Collaborations

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Abstract

We compute the leptonic decay constants fD+, fDs, and fK+, and the quark-mass ratios mc/ms and ms/ml in unquenched lattice QCD. We use the MILC highly improved staggered quark (HISQ) ensembles with four dynamical quark flavors. Our primary results are fd+ = 212.6(0.4)(+1.0 -1.2) MeV, fDs = 249.0(0.3)(+1.1 1. 5) MeV, and fDs/fD+ = 1.1712(10)(+-29 -32), where the errors are statistical and total systematic, respectively. We also obtain fK+/fπ+ = 1.1956(10) (+-26 -18), updating our previous result, and determine the quark-mass ratios ms/ml = 27.35(5)(+10 -7) and mc/ms = 11.747(19)(+59 -43). When combined with experimental measurements of the decay rates, our results lead to precise determinations of the CKM matrix elements |Vus| = 0.22487(51)(29)(20)(5), |Vcd| = 0.217(1)(5)(1) and |Vcs| = 1.010(5)(18)(6), where the errors are from this calculation of the decay constants, the uncertainty in the experimental decay rates, structure-dependent electromagnetic corrections, and, in the case of |Vus|, the uncertainty in |Vud|, respectively.

Original languageEnglish (US)
Article number382
JournalProceedings of Science
VolumePart F130500
StatePublished - 2014

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Fermilab Lattice and MILC Collaborations (2014). Charmed and light pseudoscalar meson decay constants from HISQ simulations. Proceedings of Science, Part F130500, [382].