Theoretical Status of K->pinunubar Decays

We present a concise review of the theoretical status of rare K->pinunubar decays in and beyond the standard model. Particular attention is thereby devoted to the recent calculation of the next-to-next-to-leading order corrections to the charm quark contribution of K^+->pi^+nunubar which removes the last relevant theoretical uncertainty from the K->pinunubar system.Comment: 5 pages, 2 figures, talk given at the XLIst Rencontres de Moriond QCD and High Energy Hadronic Interactions, La Thuile, Aosta Valley, Italy, March 18--25, 200

Something about Z-penguins I want to tell

We stress that in models with constrained minimal flavor violation large negative corrections to the flavor-changing Z-penguin amplitudes are excluded by the precision measurements of the Z -> b anti-b pseudo observables performed at LEP and SLC. The derived stringent range for the non-standard contribution to the universal Inami-Lim function C leads to tight two-sided limits for the branching ratios of all Z-penguin dominated flavor-changing K- and B-decays.Comment: Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 5 pages, PDFLaTeX, 2 pdf figures and 1 table; v2: LaTeX template and references update

Rare K- (vs.) B-decays

We present a concise review of the recent theoretical progress concerning the standard model calculations of the rare K_L -> pi^0 nu anti-nu, K^+ -> pi^+ nu anti-nu (gamma), anti-B -> X_s gamma, and anti-B -> X_s l^+ l^- decays. The current status and future of the model-independent analysis of rare K- and B-meson decays within constrained minimal-flavor-violation is also briefly discussed.Comment: 12 pages, 4 figures, to appear in the proceedings of the Kaon International Conference (KAON'07), Frascati, Italy, 21-25 May 2007, uses pdflatex; minor changes, final version accepted for publication on Po

How To Kill a Penguin

Within constrained minimal-flavor-violation the large destructive flavor-changing Z-penguin managed to survive eradication so far. We give a incisive description of how to kill it using the precision measurements of the Z -> b anti-b pseudo observables. The derived stringent range for the non-standard contribution to the universal Inami-Lim function C leads to tight two-sided limits for the branching ratios of all Z-penguin dominated flavor-changing K- and B-decays.Comment: 5 pages, 4 figures, 1 table, uses pdflatex, talk given at DIS 2007, Muenchen, Germany, April 15--20, 200

Recent Developments in Bbar -> X_s gamma

We present a concise review of the recent theoretical progress concerning the standard model calculation of the inclusive radiative Bbar -> X_s gamma decay. Particular attention is thereby devoted to the calculations of the next-to-next-to-leading order fixed-order O(alpha_s^2) contributions, non-local O(alpha_s Lambda/m_b) power corrections, and logarithmic-enhanced O(alpha_s^2) cut-effects to the decay rate. The current status of new physics calculations of the inclusive b -> s gamma mode is also briefly summarized.Comment: 7 pages, 2 figures, 1 table, based on invited talks given at the third meeting of the workshop ``Flavour in the era of the LHC'', CERN, Geneva, March 15--17, 2006 and at XLIInd Rencontres de Moriond, QCD and Hadronic Interactions, La Thuile, Italy, March 17--24, 2007, v2: minor modification

Complete electroweak matching for radiative B decays

We compute the complete two-loop O(alpha) Wilson coefficients relevant for radiative decays of the B meson in the SM. This is a necessary step in the calculation of the O(alpha alpha_s^n ln^n m_b/M_W) corrections and improves on our previous analysis of electroweak effects in B -> X_s gamma. We describe in detail several interesting technical aspects of the calculation and include all dominant QED matrix elements. In our final result, we neglect only terms originated from the unknown O(alpha alpha_s) evolution of the Wilson coefficients and some suppressed two-loop matrix elements. Due to the compensation among different effects, we find that non-trivial electroweak corrections decrease the branching ratio by about 3.6% for a light Higgs boson, very close to our previous result. The corresponding up-to-date SM prediction for the branching ratio with E_gamma > 1.6 GeV is (3.61 +- 0.30) x 10^-4.Comment: 20 pages, 2 figures, uses amssymb.sty, amsmath.sty and feynarts.sty. Minor change