Tadpole-improved perturbation theory for heavy-light lattice operators

Abstract

Lattice calculations of matrix elements involving heavy-light quark bilinears are of interest in calculating a variety of properties of B and D mesons, including decay constants and mixing parameters. A large source of uncertainty in the determination of these properties has been uncertainty in the normalization of the lattice-regularized operators that appear in the matrix elements. Tadpole-improved perturbation theory, as formulated by Lepage and Mackenzie, promises to reduce these uncertainties below the ten percent level at one loop. In this paper we study this proposal as it applies to lattice-regularized heavy-light operators. We consider both the commonly used zero-distance bilinear and the distance-one point-split operator. A self-contained selection on the application of these results is included. The calculation reduces the value of ${\mathit{f}}_{\mathit{B}}$ obtained from lattice calculations using the heavy quark effective theory.