D meson semileptonic form factors with HISQ valence and sea quarks

We present a calculation of the form factors of the D $\rightarrow$ Klν and D $\rightarrow$ $\pi$lν semileptonic decays at zero momentum transfer, ultimately for the purpose of determining the Cabibbo-KobayashiMaskawa (CKM) matrix elements |Vcs| and |Vcd|. This work uses MILC Nf = 2+1+1 configurations with the HISQ action for both sea quarks and valence quarks, including several physical mass ensembles and lattice spacings down to 0.042 fm. The calculation is done directly at q 2 = 0 by employing twisted boundary conditions to tune the child particle momenta. Results at the physical point and in the continuum limit will be achieved in the final analysis through the use of Heavy-Meson Staggered $\chi$PT. Here we present our expected error budget and compare with the error of prior calculations