Techniques for computing two - loop QCD corrections to b → c transitions
نویسنده
چکیده
We have recently presented the complete O(αs) corrections to the semileptonic decay width of the b quark at maximal recoil. Here we discuss various technical aspects of that calculation and further applications of similar methods. In particular, we describe an expansion which facilitates the phase space integrations and the treatment of the mixed real–virtual corrections, for which Taylor expansion does not work and the so-called eikonal expansion must be employed. Several terms of the expansion are given for theO(αs) QCD corrections to the differential semileptonic decay width of the b–quark at maximal recoil. We also demonstrate how the light quark loop corrections to the top quark decay rate can be obtained using the same methods. We briefly discuss the application of these techniques to the calculation of the O(αs) correction to zero recoil sum rules for heavy flavor transitions.
منابع مشابه
Two - loop QCD Corrections to b → c Transitions at Zero Recoil : Analytical Results
We present analytical results for the O(α s) contributions to the functions ηA and ηV which parameterize QCD corrections to semileptonic b → c transitions at zero recoil. Previously obtained approximate results are confirmed. The methods of computing the relevant twoloop diagrams with two mass scales are discussed in some detail.
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