Ulrich A. Haisch

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We calculate the charm-quark contribution to the decay K(L)-->mu(+)mu(-) in next-to-next-to-leading order of QCD. This new contribution reduces the theoretical uncertainty in the relevant parameter P(c) from +/-22% down to +/-7%, corresponding to scale uncertainties of +/-3% and +/-6% in the short-distance part of the branching ratio and the determination(More)
We calculate the complete next-to-next-to-leading order QCD corrections to the charm contribution of the rare decay K → πνν̄. We encounter several new features, which were absent in lower orders. We discuss them in detail and present the results for the twoloop matching conditions of the Wilson coefficients, the three-loop anomalous dimensions, and the(More)
We compute the complete O(α s) anomalous dimension matrix relevant for the b → sγ, b → sg and b → sll transitions in the standard model and some of its extensions. For radiative decays we confirm the results of Misiak and Münz, and of Chetyrkin, Misiak and Münz. The O(α s) mixing of four-quark into semileptonic operators is instead a new result and(More)
We complete the next-to-next-to-leading-order QCD calculation of the branching ratio for B̄ → Xsll including recent results for the three-loop anomalous dimension matrix and two-loop matrix elements. These new contributions modify the branching ratio in the low-q region, BRll, by about +2% and −2%, respectively. We furthermore discuss the appropriate(More)
We point out that the precision measurements of the pseudo observables R b , Ab, and A FB performed at LEP and SLC suggest that in models with minimal-flavor-violation the sign of the Z-penguin amplitude is identical to the one present in the standard model. We determine the allowed range for the non-standard contribution to the Inami-Lim function C and(More)
We compute the two–loop electroweak corrections to the radiative decays of the B meson in the SM. Electroweak effects reduce the Wilson coefficient C 7 (MW ) by 2.6% for a light Higgs boson of about 100 GeV and are less important for a heavier Higgs. The leading term of a heavy top expansion of our result differs from the one obtained in the gaugeless(More)
We calculate the O(αs) corrections to the Z-penguin and electroweak box diagrams relevant for non-leptonic ∆F = 1 decays with F = S,B. This calculation provides the complete O(αWαs) and O(αWαs sin θWmt ) corrections (αW = α/ sin θW ) to the Wilson coefficients of the electroweak penguin four quark operators relevant for non-leptonic Kand B-decays. We argue(More)