David M. Straub

Symmetries and asymmetries of B → K*μ+μ− decays in the Standard Model and beyond

The rare decay B → K*(→ Kπ)μ+μ− is regarded as one of the crucial channels for B physics as the polarization of the K* allows a precise angular reconstruction resulting in many observables that offer new important tests of the Standard Model and its extensions. These angular observables can be expressed in terms of CP-conserving and CP-violating quantities which we study in terms of the full form factors calculated from QCD sum rules on the light-cone, including QCD factorization corrections. We investigate all observables in the context of the Standard Model and various New Physics models, in particular the Littlest Higgs model with T-parity and various MSSM scenarios, identifying those observables with small to moderate dependence on hadronic quantities and large impact of New Physics. One important result of our studies is that new CP-violating phases will produce clean signals in CP-violating asymmetries. We also identify a number of correlations between various observables which will allow a clear distinction between different New Physics scenarios.

Anatomy and phenomenology of FCNC and CPV effects in SUSY theories

Abstract We perform an extensive study of FCNC and CP Violation within Supersymmetric (SUSY) theories with particular emphasis put on processes governed by b → s transitions and of their correlations with processes governed by b → d transitions, s → d transitions, D 0 – D ¯ 0 oscillations, lepton flavour violating decays, electric dipole moments and ( g − 2 ) μ . We first perform a comprehensive model-independent analysis of Δ F = 2 observables and we emphasize the usefulness of the R b – γ plane in exhibiting transparently various tensions in the present UT analyses. Secondly, we consider a number of SUSY models: the general MSSM, a flavour-blind MSSM, the MSSM with Minimal Flavour Violation as well as SUSY flavour models based on Abelian and non-Abelian flavour symmetries that show representative flavour structures in the soft SUSY breaking terms. We show how the characteristic patterns of correlations among the considered flavour observables allow to distinguish between these different SUSY scenarios. Of particular importance are the correlations between the CP asymmetry S ψ ϕ and B s → μ + μ − , between the anomalies in S ϕ K S and S ψ ϕ , between S ϕ K S and d e , between S ψ ϕ and ( g − 2 ) μ and also those involving lepton flavour violating decays. In our analysis, the presence of right-handed currents and of the double Higgs penguin contributions to B s mixing plays a very important role. We propose a “DNA-Flavour Test” of NP models including Supersymmetry, the Littlest Higgs model with T-parity and the Randall–Sundrum model with custodial protection, with the aim of showing a tool to distinguish between these NP scenarios, once additional data on flavour-changing processes become available. As a byproduct, we present the SM prediction for BR ( B + → τ + ν ) = ( 0.80 ± 0.12 ) × 10 − 4 that follows solely from an analytical formula for this branching ratio in terms of Δ M s , d and S ψ K S asymmetry and which does not involve V u b and F B uncertainties.

B →Vℓ+ℓ− in the Standard Model from light-cone sum rules

A bstractWe present Bq → ρ, Bq → ω, Bq → K∗, Bs → K∗ and Bs → ϕ form factors from light-cone sum rules (LCSR) at Oαs

Flavour physics from an approximate U(2)3 symmetry

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Cornering new physics in b → s transitions

for twist-2 and 3 and Oαs0

SUSY GUTs with Yukawa unification: A go/no-go study using FCNC processes

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