PQCD study of the [Formula Presented] and [Formula Presented] controversy in inclusive [Formula Presented] decays

We calculate the semileptonic branching fraction and charm yield from inclusive (Formula presented) decays using the formalism of perturbative QCD. For nonleptonic decays, we employ the modified factorization theorem, in which Wilson coefficients evolve with the characteristic scales of the decay modes. It is found that the decay rate of the single-charm mode (Formula presented) is enhanced, and a lower (Formula presented) is obtained without increasing (Formula presented) This conclusion differs from the usual one, where the (Formula presented) mode is increased. Our result for the (Formula presented) meson lifetime is also consistent with the data.