Point-Split Lattice Operators for B Decays

The matrix element which determines the B meson decay constant can be measured on the lattice using an effective field theory for heavy quarks. Various discretizations of the heavy-light bilinears which appear in this and other B decay matrix elements are possible. The heavy-light bilinear currently used for the determination of the B meson decay constant on the lattice suffers a substantial one-loop renormalization. In this paper, we compute the one-loop renormalizations of the discretizations in which the heavy and light fields in the bilinear are separated by one lattice spacing, and discuss their application. Readers of this paper may also be interested in our paper on the application of Symanzik's improvement program to heavy-light currents (paper number 9203221 on hep-ph).