Four-fermion heavy quark operators and light current amplitudes in heavy flavor hadrons - art. no. 034012

We introduce and study the properties of the "color-straight" four-quark op erators containing heavy and light quark fields. They are of the form ((b) over bar Gamma(b)b)((q) over bar Gamma(q)q) where both brackets are color s inglets. Their expectation values include the bulk of the nonfactorizable c ontributions to the nonleptonic decay widths of heavy hadrons. The expectat ion values of the color-straight operators in the heavy hadrons are related to momentum integrals of the elastic light-quark form factors of the respe ctive heavy hadron. We calculate the asymptotic behavior of the light-curre nt form factors of heavy hadrons and show that the actual decrease is 1/(q( 2))(3/2) rather than 1/q(4). The two-loop hybrid anomalous dimensions of th e four-quark operators and their mixing (absent in the first loop) are obta ined. Using plausible-models for the elastic form factors, we estimate the expectation values of the color-straight operators in the heavy mesons and baryons. Improved estimates will be possible in the future with new data on the radiative decays of heavy hadrons. We give the Wilson coefficients of the four-fermion operators in the 1/m(b) expansion of the inclusive widths and discuss the numerical predictions for the lifetime ratios. Estimates of the nonfactorizable expectation values are given. [S0556-2821(99)07601-8].