We present results for form factors of semileptonic decays of D and B mesons in 2 + 1 flavor lattice QCD using the MILC gauge configurations. With an improved staggered action for light quarks, we successfully reduce the systematic error from the chiral extrapolation. The results for D decays are in agreement with experimental ones. The results for B decays are preliminary. Combining our results with experimental branching ratios, we then obtain the CKM matrix elements Vcd , Vcs , Vcb and Vub . We also check CKM unitarity, for the first time, using only lattice QCD as the theoretical input.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics