Three-loop anomalous dimension of the heavy-light quark current in HQET

Abstract

The anomalous dimension of the heavy-light quark current in HQET is calculated with three-loop accuracy, as well as the renormalized heavy-quark propagator. The NNL perturbative correction to f_B/f_D is obtained.

Comments: 16 pages, 7 eps figures. Typos in the discussion of fB/fD corrected. Paper is also available at http://www-ttp.physik.uni-karlsruhe.de/Preprints/ Results and REDUCE programs are available at http://www-ttp.physik.uni-karlsruhe.de/Progdata/ttp03/ttp03-10/