QCD Factors a 1 and a 2 Beyond Leading Logarithms versus Factorization in Non - leptonic Heavy Meson Decays ∗

نویسنده

  • Andrzej J. Buras
چکیده

We calculate the QCD factors a1 and a2, entering the tests of factorization in nonleptonic heavy meson decays, beyond the leading logarithmic approximation in three renormalization schemes (NDR, HV, DRED). We investigate their μ–dependence and the renormalization scheme dependence. We point out that a1 for B-decays depends very weakly on ΛMS, μ and the choice of the renormalization scheme. For Λ (5) MS = 225±85MeV and 4 GeV ≤ μ ≤ 8 GeV we find a1 = 1.01±0.02 in accordance with phenomenology. The ΛMS, μ and scheme dependences of a2 are on the other hand sizable. Interestingly, for the NDR scheme we find a 2 = 0.20± 0.05, in the ball park of recent phenomenological results and substantially larger than leading order estimates. However a 2 = 0.16± 0.05 and a 2 = 0.15± 0.05. Implications of these findings for the tests of factorization in B-decays and D-decays are critically discussed. ∗Supported by the German Bundesministerium für Forschung und Technologie under contract 06 TM 732 and by the CEC science project SC1–CT91–0729.

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تاریخ انتشار 1994