====== TTP09-27 Tree-level contributions to the rare B+ --> X+ nu nu bar decays in the Standard Model ======
 
 
   <hidden TTP09-27  Tree-level contributions to the rare B+ --> X+ nu nu bar decays in the Standard Model > The tree-level contributions to the rare decays B+ --> pi+ nu anti-nu, B+ --> K+ nu anti-nu, and B+ --> K*+ nu anti-nu are analyzed and compared to those occurring in K+ --> pi+ nu anti-nu, D+ --> pi+ nu anti-nu, and Ds+ --> pi+ nu anti-nu. It is shown that these purely long-distance contributions, arising from the exchange of a charged lepton, can be significant in B+ decays for an intermediate tau, potentially blurring the distinction between the modes used to extract B --> tau nu and those used to probe the genuine short-distance b --> (s,d) nu anti-nu FCNC transitions. Numerically, the tree-level contributions are found to account for 97%, 12% and 14% of the total B+ --> pi+ nu anti-nu, B+ --> K+ nu anti-nu, and B+ --> K*+ nu anti-nu rates, respectively.
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|**Jernej F. Kamenik and Christopher Smith**  | 
|**  Phys.Lett.  B680 471-475 2009  **  |
| {{preprints:2009:ttp09-27.pdf|PDF}} {{preprints:2009:ttp09-27.ps|PostScript}} [[http://arxiv.org/abs/0908.1174|arXiv]]   |
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