Penguin pollution in β\beta and βs\beta_s

The mixing-induced CP asymmetries in $B_d \to J/\psi K_S$ and $B_s \to J/\psi \phi$ are essential to detect or constrain new physics in the $B_d\! - \overline{\!B}{}_d$ and $B_s\! - \overline{\!B}{}_s$ mixing amplitudes, respectively. To this end one must control the penguin contributions to the decay amplitudes, which affect the extraction of fundamental CP phases from the measured CP asymmetries. Although the "penguin pollution" is doubly Cabibbo-suppressed, it could compete in size with current experimental errors. In this talk I present a calculation of the penguin contributions treating QCD effects with soft-collinear factorisation and compare method and results with the alternative approach employing flavour-SU(3) symmetry. As a novel feature, I present results for the penguin pollution in $b\to c\overline c d$ modes.Comment: Talk at CKM2016, 28 November - 3 December 2016 Tata Institute for Fundamental Research (TIFR), Mumbai, Indi

The width difference of B_s mesons

Next-to-leading order QCD corrections to the width difference Delta Gamma in the B_s-meson system are presented. I further discuss how Delta Gamma can be used to detect new physics.Comment: 10 pages, talk at RADCOR 2000, Carmel, US

Flavor physics within and beyond the Standard Model

I review recent progress in theoretical calculations related to the CKM unitarity triangle. After briefly discussing hints for new physics in B_d-B_d-bar mixing and B_s-B_s-bar mixing I present three topics of MSSM flavor physics: First I discuss new tan-beta-enhanced radiative corrections to flavor-changing neutral current (FCNC) amplitudes which go beyond the familiar Higgs-mediated FCNC diagrams and may enhance the mixing-induced CP asymmetry in B_d -> phi K_S. The second topic is a reappraisal of the idea that flavor violation originates from the soft supersymmetry-breaking terms. Finally I discuss how mu -> e gamma can be used to constrain the flavor structure of the dimension-5 Yukawa interactions which appear in realistic grand unified theories.Comment: 10 pages, talk at "Rencontres de Physique de la Vall\'ee d'Aoste", La Thuile, Italy, Feb 28 -- Mar 6, 201

QCD corrections to lifetime differences of B_s mesons

The calculation of QCD corrections to the width difference Delta Gamma in the B_s meson system is presented. The next-to-leading order corrections reduce the dependence on the renormalization scale significantly and allow for a meaningful use of hadronic matrix elements from lattice gauge theory. At present the uncertainty of the lattice calculations limits the prediction of Delta Gamma. The presented work has been performed in collaboration with Martin Beneke, Gerhard Buchalla, Christoph Greub and Alexander Lenz.Comment: Talk at "4th Workshop on Continuous Advances in QCD," 12-14 May 2000, Minneapolis, Minnesota, US