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Semileptonic Decays of D Mesons in Three-Flavor Lattice QCD

2005; American Physical Society; Volume: 94; Issue: 1 Linguagem: Inglês

10.1103/physrevlett.94.011601

1092-0145

Christopher Aubin, C. Bérnard, Carleton DeTar, Massimo Dipierro, A. X. El-Khadra, Steven Gottlieb, Eric B. Gregory, Urs M. Heller, J. E. Hetrick, Andreas S. Kronfeld, Paul B. Mackenzie, D. Menscher, M. Nobes, M. Okamoto, M. B. Oktay, James C. Osborn, James N. Simone, R. Sugar, D. Toussaint, Howard D. Trottier,

High-Energy Particle Collisions Research

We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC Collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently, the systematic error from the chiral extrapolation is much smaller than in previous calculations with Wilson-type light quarks. Our results for the form factors at q(2)=0 are f(D-->pi)(+)(0)=0.64(3)(6) and f(D-->K)(+)(0)=0.73(3)(7), where the first error is statistical and the second is systematic, added in quadrature. Combining our results with experimental branching ratios, we obtain the Cabibbo-Kobayashi-Maskawa matrix elements |V(cd)|=0.239(10)(24)(20) and |V(cs)|=0.969(39)(94)(24), where the last errors are from experimental uncertainties.