Semileptonic B decays from a NRQCD and D234 action

Semileptonic, B→pi l (ν) over bar, decays are studied on quenched anisotropic lattices using tree-level tadpole improved Symanzik glue, nonrelativistic QCD heavy quark and D234 light quark actions. Constrained fitting methods are applied to extract ground state contributions to two-point and three-point correlators. We agree with previous lattice determinations of the form factors. The major source of systematic error here, as in previous work, comes from the chiral extrapolation to the physical pion mass. Future calculations must work at lighter quark masses to resolve this.