2-loop QCD corrections to Bc-meson leptonic constant

Abstract

We present results for two-loop QCD corrections to the short distance coefficient that governs leptonic decay of Bc-meson. After brief discussion of the technics of asymptotic threshold expansion used to perform this calculation, we give comments on the numerical value of two-loop corrections and its impact on NRQCD description of Bc-meson bound state dynamics.

Comments: 12 pages, 1 figure, v2: typos in appendix corrected; v3: Mathematica ant text files with results attached