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arXiv · hep-ph/0611108

|V_ub| from UTangles and B->pi l nu

Patricia Ball
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Abstract

The angles of the CKM unitarity triangle are now known well enough to allow a determination of its sides from global fits, with good accuracy. Assuming that new physics does not affect the angles, UTfit and CKMfitter find $|V_{ub}| = (3.50\pm 0.18)\times 10^{-3}$. Using this result, and new high-precision data on the spectrum of $B\toπ\ellν$ decays from BaBar, we find $|V_{ub}| f_+(0) = (9.1\pm 0.7)\times 10^{-4}$ and $f_+(0) = 0.26\pm 0.02$, with $f_+$ the $B\toπ$ weak transition form factor. These results are {\em completely model-independent}. We compare them to theoretical calculations from lattice and QCD sum rules on the light-cone.

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Patricia Ball. 2006-11-08. |V_ub| from UTangles and B->pi l nu. https://doi.org/10.1016/j.physletb.2006.11.034

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