D semileptonic form factors and |V_cs(d)| from 2+1 flavor lattice QCD

Understand

The measured partial widths of the semileptonic decays D to K l nu and D to pi l nu can be combined with the form factors calculated on the lattice to extract the CKM matrix elements |V_cs| and |V_cd|.

• The lattice calculations can be checked by comparing the form factor shapes from the lattice and experiment.
• We have generated a sizable data set by using heavy clover quarks with the Fermilab interpretation for charm and asqtad staggered light quarks on 2+1 flavor MILC ensembles with lattice spacings of approximately 0.12, 0.09, 0.06, and 0.045 fm.
• Preliminary fits to staggered chiral perturbation theory suggest that we can reduce the uncertainties in the form factors at zero invariant mass to below 5%.