NONFACTORIZABLE SOFT GLUONS IN NONLEPTONIC HEAVY MESON DECAYS

We include nonfactorizable soft gluon corrections to the perturbative QCD formalism for exclusive nonleptonic heavy meson decays, which comb ines factorization theorems and effective field theory. These correcti ons are classified according to their color structures, and exponentia ted separately to complete the Sudakov resummation up to next-to-leadi ng logarithms. The nonfactorizabIe contributions in nonleptonic decays are clearly identified in our formalism, and found to be positive for bottom decays and negative for charm decays. Our analysis confirms th at the large-N-c approximaton is applicable to charm decays, but not t o bottom decays, consistent with the phenomenological implications of experimental data. The comparision of our predictions with those from QCD sum rules is also made. [S0556-2821(97)05923-7].