Shape-function independent relations of charmless inclusive B-decay spectra
نویسنده
چکیده
A leading-power factorization formula for weight functions relating the B̄ → Xsγ photon spectrum to arbitrary partial decay rates in B̄ → Xu lν̄ is derived. These weight functions are independent of the hadronic shape function and allow for the determination of |Vub| in a model-independent way. We calculate the weight function in renormalizationgroup improved perturbation theory to complete next-to-next-to leading order at the jet scale μi ∼ mbΛQCD and to next-to leading order at the hard scale μh ∼ mb. First-order power corrections are also included, where a model-dependence enters via the appearance of subleading hadronic shape functions.
منابع مشابه
ar X iv : h ep - p h / 06 01 18 1 v 1 21 J an 2 00 6 Progress in computing inclusive B decay spectra
We review the progress in the QCD calculation of inclusive decay spectra. It was recently shown that the inherent infrared finiteness of inclusive spectra extends beyond the level of logarithms. Dressed Gluon Exponentiation makes practical use of this property by computing the Sudakov exponent as a Borel sum. Based on renormalon analysis, infrared sensitivity in the exponent is reflected in pow...
متن کاملcharmless semileptonic branching ratio of b hadrons
We calculate the inclusive charmless semileptonic decay width of the B meson using a QCD-based approach. This approach is able to account for both dynamic and kinematic effects of nonperturbative QCD. The charmless semileptonic decay width is found to be enhanced by long-distance strong interactions by +(7± 5)% with respect to the free quark decay width. Using the resulting theoretical value fo...
متن کاملFirst Measurement of the Inclusive Charmless B Decay Branching Ratio and Determination of the B ! C Cs Rate Delphi Collaboration Delphi Collaboration Measurement of the Inclusive Charmless and Double Charm B Decay Branching Ratios with the B-tagging Probability Technique
A measurement of the inclusive B decay branching ratios into charmless and double charmed nal states has been performed, using the data collected by the DELPHI experiment at LEP from 1992 to 1995, by mean of two diierent techniques that are presented in two diierent notes. In the rst analysis, the results are extracted from a t to the b-tagging probability distribution based on the precise impa...
متن کاملUOM/NPh/HQP/00-3 UH-511-962-00 Inclusive charmless semileptonic decay of Λb and Br(b → Xulνl)
We study the inclusive charmless semileptonic decay of Λb, Λb → Xulνl, in the framework of heavy quark expansion and find that the rate is substantially enhanced by spectator effect. We obtain Br(b → Xulνl) to be 1.13× 10 −3 for |Vub| = 3.3× 10 . We discuss our result in light of the recent LEP measurements of the charmless semileptonic branching ratio where such enhancement was not taken into ...
متن کاملModel-independent determination of |Vub|
The decay distribution of the kinematic variable ξu in inclusive charmless semileptonic decays of B mesons is unique. The novel method for a model-independent determination of |Vub| is described. To appear in Proceedings of the 3rd International Conference on B Physics and CP Violation Taipei, Taiwan, December 3-7, 1999 MODEL-INDEPENDENT DETERMINATION OF |Vub| CHANGHAO JIN School of Physics, Un...
متن کامل