Heavy-light meson decay constants with N_f = 3

INTRODUCTION We are extending a calculation of heavy-light meson decay constants with three avors of dynamical quarks that was begun last year [1]. In addition to increasing statistics on some runs, we have additional mass combinations for a = 0:13 fm and new dynamical quark runs with a = 0:09 fm. Runs for the coarser lattice spacing are completed, but running will continue for the ner lattice spacing, so that we can begin to understand the continuum limit. Dynamical gauge con gurations are generated using the Asqtad action [2]. The gauge action includes the plaquette, 1 2 rectangles and the \bent-chair" or \parallelogram" six-link operator. The quark action includes the Naik 3-link term and fat-link terms up to seven links long in addition to the usual staggered quark terms. For the heavy-light mesons, we use tadpoleimproved Clover valence quarks and operators that are improved according to the Fermilab formalism [3]. For each ensemble of dynamical quark con gurations, we us