TY - JOUR

T1 - Four-fermion heavy quark operators and light current amplitudes in heavy flavor hadrons

AU - Pirjol, Dan

PY - 1999

Y1 - 1999

N2 - We introduce and study the properties of the “color-straight” four-quark operators containing heavy and light quark fields. They are of the form (Formula presented) where both brackets are color singlets. Their expectation values include the bulk of the nonfactorizable contributions to the nonleptonic decay widths of heavy hadrons. The expectation values of the color-straight operators in the heavy hadrons are related to momentum integrals of the elastic light-quark form factors of the respective heavy hadron. We calculate the asymptotic behavior of the light-current form factors of heavy hadrons and show that the actual decrease is (Formula presented) rather than (Formula presented) The two-loop hybrid anomalous dimensions of the four-quark operators and their mixing (absent in the first loop) are obtained. 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 (Formula presented) expansion of the inclusive widths and discuss the numerical predictions for the lifetime ratios. Estimates of the nonfactorizable expectation values are given.

AB - We introduce and study the properties of the “color-straight” four-quark operators containing heavy and light quark fields. They are of the form (Formula presented) where both brackets are color singlets. Their expectation values include the bulk of the nonfactorizable contributions to the nonleptonic decay widths of heavy hadrons. The expectation values of the color-straight operators in the heavy hadrons are related to momentum integrals of the elastic light-quark form factors of the respective heavy hadron. We calculate the asymptotic behavior of the light-current form factors of heavy hadrons and show that the actual decrease is (Formula presented) rather than (Formula presented) The two-loop hybrid anomalous dimensions of the four-quark operators and their mixing (absent in the first loop) are obtained. 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 (Formula presented) expansion of the inclusive widths and discuss the numerical predictions for the lifetime ratios. Estimates of the nonfactorizable expectation values are given.

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U2 - 10.1103/PhysRevD.59.034012

DO - 10.1103/PhysRevD.59.034012

M3 - Article

SN - 1550-7998

VL - 59

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

IS - 3

ER -