Inclusive nonleptonic decays of $B$ and $D$ mesons are investigated to leading order and next-to-leading order in $\frac{1}{m_Q}$. QCD corrections to the leading order ($m_Q^5$) term give the most essential contribution to the observed enhancement. Various inclusive bound-state production processes are dealt with in the factorization approximation. A good semiquantitative understanding of the data has been achieved and the role of the spectator quark for the lifetime difference between $D^0$ and $D^{+}$ is clarified. A search for missing decays in the $b\to c \overline{c} s$ channel is suggested.

• Received 24 May 1993

DOI:https://doi.org/10.1103/PhysRevD.48.4174