Penguin Diagrams, Charmless B-Decays and the ``Missing Charm Puzzle''
Abstract
We calculate the contributions of penguin diagrams with internal u or c quarks to various inclusive charmless B-decay rates. Further we analyze the influence of the chromomagnetic dipole operator Q8 on these rates. We find that the rates corresponding to B-bar --> Xu u-bar s, B-bar --> Xd d-bar s, B-bar --> Xs s-bar s, B-bar --> Xs s-bar d and B --> Xd d-bar d are dominated by the new penguin contributions. The contributions of Q8 sizably diminish these rates. Despite of an increase of the total charmless decay rate by 36 % the new contributions are not large enough to explain the charm deficit observed by ARGUS and CLEO. We predict nc=1.33 +/- 0.06 for the average number of charmed particles per B-decay in the Standard Model. Then the hypothesis of an enhancement of the chromomagnetic dipole coefficient C8 by new physics contributions is analyzed. We perform a model independent fit of C8 to the experimental data. If the CKM structure of the new physics contribution is the same as in the Standard Model, |C8(MW)| must be enhanced by a factor of 9 to 16 in order to explain the observed charm deficit.
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