A Comment on the Extractions of Vub from Radiative Decays
نویسندگان
چکیده
We present a model independent closed form expression for |Vub| /|VtbV ∗ ts| 2, which includes the resummation of large endpoint logarithms as well as the interference effects from the operators O2 and O8. We demonstrate that the method to extract |Vub| presented by the authors in hep-ph/9909404, and modified in this letter to include interference effects, is not just a refinement of the method described by Neubert in hep-ph/9312311. Indeed, we show that Neubert’s proposal is incorrect at order αs. We also point out that, contrary to what was recently claimed by Neubert in hep-ph/0104280, when the present experimental cut is used, the resummation is not negligible and that the Landau pole does not introduce any significant uncertainties.
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