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arXiv · hep-ph/0209075

Pade/renormalization-group improvement of inclusive semileptonic B decay rates

M. R. Ahmady·F. A. Chishtie·V. Elias·A. H. Fariborz·D. G. C. McKeon·T. N. Sherry·T. G. Steele
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Abstract

Renormalization Group (RG) and optimized Pade-approximant methods are used to estimate the three-loop perturbative contributions to the inclusive semileptonic b \to u and b \to c decay rates. It is noted that the \bar{MS} scheme works favorably in the b \to u case whereas the pole mass scheme shows better convergence in the b \to c case. Upon the inclusion of the estimated three-loop contribution, we find the full perturbative decay rate to be 192π^3Γ(b\to u\barν_\ell\ell^-)/(G_F^2| V_{ub}|^2) = 2065 \pm 290{\rm GeV^5} and 192π^3Γ(b\to c\ell^-\barν_\ell)/(G_F^2|V_{cb}|^2)= 992 \pm 198 {\rm GeV^5}, respectively. The errors are inclusive of theoretical uncertainties and non-perturbative effects. Ultimately, these perturbative contributions reduce the theoretical uncertainty in the extraction of the CKM matrix elements |V_{ub}| and |V_{cb}| from their respective measured inclusive semileptonic branching ratio(s).

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M. R. Ahmady, F. A. Chishtie, V. Elias, A. H. Fariborz, D. G. C. McKeon, T. N. Sherry, T. G. Steele. 2002-09-06. Pade/renormalization-group improvement of inclusive semileptonic B decay rates. https://doi.org/10.1016/s0920-5632(02)01958-8

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