We present the first three-flavor lattice QCD calculations for D →πlv and D →Klv 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 q2 = 0 are f+D→π(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 |Vcd| = 0.239(10)(24)(20) and |V cs| = 0.969(39)(94)(24), where the last errors are from experimental uncertainties.
ASJC Scopus subject areas
- Physics and Astronomy(all)