$B_{(s)}\to D_{(s)}$ semileptonic decays with NRQCD-HISQ valence quarks
  We present a calculation of the form factors, $f_0$ and $f_+$, for the $B_{(s)} \to D_{(s)}$ semileptonic decays. Our work uses the MILC $n_f=2+1$ AsqTad configurations with NRQCD and HISQ valence quarks at four values of the momentum transfer $q^2$. We provide results for the chiral-continuum extrapolations of the scalar and vector form factors. 
Christopher J. Monahan, Heechang Na, Chris M. Bouchard, G. Peter   Lepage, Junko Shigemitsu
hep-lat