QCD RADIATIVE-CORRECTIONS TO THE LEPTONIC DECAY-RATE OF THE B-C MESON

The QCD radiative corrections to the leptonic decay rate of the Bc meson are calculated using the formalism of nonrelativistic QCD (NRQCD) to separate short-distance and long-distance effects. The Bc decay constant is factored into a sum of NRQCD matrix elements each multiplied by a short-distance coefficient. The short-distance coefficient for the leading matrix element is calculated to order αs by matching a perturbative calculation in full QCD with the corresponding perturbative calculation in NRQCD. This short-distance correction decreases the leptonic decay rate by approximately 15%. © 1995 The American Physical Society.