https://biblio.ugent.be/publication/685594/file/1130605.pdf

Review of Particle Physics

We review the present status of QCD corrections to weak decays beyond the leading-logarithmic approximation, including particle-antiparticle mixing and rare and $\mathrm{CP}$-violating decays. After presenting the basic formalism for these calculations we discuss in detail the effective Hamiltonians of all decays for which the next-to-leading-order corrections are known. Subsequently, we present the phenomenological implications of these calculations. The values of various parameters are updated, in particular the mass of the newly discovered top quark. One of the central issues in this review are the theoretical uncertainties related to renormalization-scale ambiguities, which are substantially reduced by including next-to-leading-order corrections. The impact of this theoretical improvement on the determination of the Cabibbo-Kobayashi-Maskawa matrix is then illustrated. [S0034-6861(96)00304-2]

Weak decays beyond leading logarithms

This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.

/pdf/averages-of-b-hadron-c-hadron-and-tau-lepton-properties-as-29qrkk2j2g.pdf

Averages of b-hadron, c-hadron, and tau-lepton properties as of early 2012

https://cds.cern.ch/record/566059/files/arXiv:hep-ph_0207036.pdf

Minimal flavour violation: an effective field theory approach

/pdf/review-of-particle-physics-1996-1997-jeg703df6k.pdf

Review of Particle Physics, 1996-1997

We provide a model-independent framework for the analysis of the radiative B-meson decays B -> K* gamma and B -> rho gamma. In particular, we give a systematic discussion of the various contributions to these exclusive processes based on the heavy-quark limit of QCD. We propose a novel factorization formula for the consistent treatment of B -> V gamma matrix elements involving charm (or up-quark) loops, which contribute at leading power in Lambda_QCD/m_B to the decay amplitude. Annihilation topologies are shown to be power suppressed. In some cases they are nevertheless calculable. The approach is similar to the framework of QCD factorization that has recently been formulated for two-body non-leptonic B decays. These results allow us, for the first time, to compute exclusive b -> s(d) gamma decays systematically beyond the leading logarithmic approximation. We present results for these decays complete to next-to-leading order in QCD and to leading order in the heavy-quark limit. Phenomenological implications for various observables of interest are discussed, including direct CP violation, and isospin and U-spin breaking effects.

The Radiative Decays B -> V gamma at Next-to-Leading Order in QCD

In strong dynamical schemes for electroweak symmetry breaking the third generation must be treated in a special manner, owing to the heavy top quark. This potentially leads to new flavor physics involving the members of the third generation in concert with the adjoining generations, with potential novel effects in b-flavored and charm physics. We give a general discussion and formulation of this kind of physics, abstracted largely from top-color models which we elaborate in detail. We identify sensitive channels for such new physics accessible to current and future experiments. \textcopyright{} 1996 The American Physical Society.

GIM violation and new dynamics of the third generation

We use the heavy quark expansion to investigate the width difference $\ensuremath{\Delta}{\ensuremath{\Gamma}}_{{B}_{s}}$ between the ${B}_{s}$ mass eigenstates. The corrections of $O(\frac{{\ensuremath{\Lambda}}_{\mathrm{QCD}}}{{m}_{b}})$ and $O(\frac{{m}_{s}}{{m}_{b}})$ to the leading-order expression in the operator product expansion are derived and estimated to yield a sizable reduction of the leading result for $\ensuremath{\Delta}{\ensuremath{\Gamma}}_{{B}_{s}}$ by typically 30%. For completeness we also quantify small effects due to penguin operators and CKM-suppressed contributions. Based on our results we discuss the prediction for ${(\frac{\ensuremath{\Delta}\ensuremath{\Gamma}}{\ensuremath{\Gamma}})}_{{B}_{s}}$ with particular emphasis on theoretical uncertainties. We find ${(\frac{\ensuremath{\Delta}\ensuremath{\Gamma}}{\ensuremath{\Gamma}})}_{{B}_{s}}={0.16}_{\ensuremath{-}0.09}^{+0.11}$, where the large error is dominated by the uncertainty in hadronic matrix elements. An accuracy of about 10% in ${(\frac{\ensuremath{\Delta}\ensuremath{\Gamma}}{\ensuremath{\Gamma}})}_{{B}_{s}}$ should be within reach, assuming continuing progress in lattice calculations. In addition, we address phenomenological issues and implications of a $\ensuremath{\Delta}{\ensuremath{\Gamma}}_{{B}_{s}}$ measurement for constraints on $\ensuremath{\Delta}{M}_{{B}_{s}}$ and CKM parameters. We further consider in some detail the lifetime ratio $\frac{\ensuremath{\tau}({B}_{s})}{\ensuremath{\tau}({B}_{d})}$ and estimate that, most likely, $|\frac{\ensuremath{\tau}({B}_{s})}{\ensuremath{\tau}({B}_{d})}\ensuremath{-}1|l1%$.

Width difference in the B s − B ¯ s system

We consider the Standard Model as an effective theory at the weak scale v of a generic new strong interaction that dynamically breaks electroweak symmetry at the energy scale Λ ~ (few) TeV. Assuming only the minimal field content with the Standard Model fermions and gauge bosons, but without a light Higgs particle, we construct the complete Lagrangian through next-to-leading order, that is, including terms of order v
 2
 /Λ2. The systematics behind this expansion is clarified. Although similar to chiral perturbation theory, it is not governed by the dimension of operators alone, but depends in an essential way on the loop expansion. Power-counting formulas are derived that indicate the classes of operators required at the next-to-leading order. The complete set of operators at leading and next-to-leading order is then listed, based on the restrictions implied by the Standard Model gauge symmetries. We recover the well-known operators discussed in the literature in connection with the electroweak chiral Lagrangian and in similar contexts, but we collect a complete and systematic list of all terms through order v
 2
 /Λ2. This includes some operators not discussed in explicit terms before. We also show that a few of the previously considered operators can be eliminated via the equations of motion. As another important result we confirm the known list of dimension-6 operators in the Standard Model with an elementary Higgs doublet, essentially as a special case of our scenario.

Gerhard Buchalla

Papers

Weak decays beyond leading logarithms

The Radiative Decays B -> V gamma at Next-to-Leading Order in QCD

GIM violation and new dynamics of the third generation

Width difference in the B s − B ¯ s system

Effective theory of a dynamically broken electroweak Standard Model at NLO