| DATE: |
2006-04-18 16:00 - 17:00 |
| PLACE: |
Room 345 in the building 4 |
| TITLE: |
Physics Seminar: A Perturbative Description of B Decay spectra and the Extraction of V_ub |
| CONTACT: |
shigeru.odaka kek.jp, 4342 |
| SPEAKER: |
Jeppe R. Andersen (Cambridge University) |
| LANGUAGE: |
English |
| URL: |
http://seminar.kek.jp/physics/index.html |
| ABSTRACT: |
We present new results obtained in a recently developed approach to the calculation of B Decay spectra. By observing that infra-red safety of decay spectra extends beyond logarithmic accuracy, the separation of perturbative and non-perturbative effects can be performed at the power level instead of the usual logarithmic level. The total effect of the non-perturbative component of the prediction is thus reduced, and a very good description of the hadronic decay spectrum is obtained already by a perturbative calculation of the on-shell decay of a b-quark. In this way, the shape and normalisation of spectra are obtained without non-perturbative input in the form of a "shape-function".
The framework can be tested by comparing the prediction to the measured spectrum in $B\to X_s\gamma$, before utilising it in the describtion of charmless semi-leptonic decays $B\to X_u l\bar\nu$ and the extraction of $|V_{ub}|$. |
