====== TTP03-12 Estimate of Charming Penguin Contributions in $B \to \pi\pi$ from QCD Light-Cone Sum Rules ======
 
 
   <hidden TTP03-12  Estimate of Charming Penguin Contributions in $B \to \pi\pi$ from QCD Light-Cone Sum Rules > Employing the QCD light-cone sum rule approach we calculate the B -> pi pi hadronic matrix element of the current-current operator with c quarks in the penguin topology (``charming penguin''). The
        dominant contribution to the sum rule is due to the c-quark loop at short distances and is of O(alpha_s) with respect to the factorizable B -> pi pi amplitude. The effects of soft gluons are suppressed at least
        by O(alpha_s m_b^{-2}). Our result indicates that sizable nonperturbative effects generated by charming penguins at finite m_b are absent. The same is valid for the penguin contractions of the
        current-current operators with light quarks. 
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|**A. Khodjamirian, Th. Mannel, B.Melic**  | 
|**  Phys.Lett.  B571 75-84 2003  **  |
| {{preprints:2003:ttp03-12.pdf|PDF}} {{preprints:2003:ttp03-12.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0304179|arXiv]]   |
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