Tobias Hurth

Optimizing the basis of B → K*ℓ+ℓ− observables in the full kinematic range

A bstractWe discuss the observables for the B → K*(→ Kπ)ℓ+ℓ− decay, focusing on both CP-averaged and CP-violating observables at large and low hadronic recoil with special emphasis on their low sensitivity to form-factor uncertainties. We identify an optimal basis of observables that balances theoretical and experimental advantages, which will guide the New Physics searches in the short term. We discuss some advantages of the observables in the basis, and in particular their improved sensitivity to New Physics compared to other observables. We present predictions within the Standard Model for the observables of interest, integrated over the appropriate bins including lepton mass corrections. Finally, we present bounds on the S-wave contribution to the distribution coming from the

On the anomalies in the latest LHCb data

Bto K_0^{*}{ell^{+}}{ell^{-}}

Global fits to b → sℓℓ data and signs for lepton non-universality

decay, which will help to establish the systematic error associated to this pollution.

On the LHCb anomaly in B → K*ℓ+ℓ−

Abstract Depending on the assumptions on the power corrections to the exclusive b → s l + l − decays, the latest data of the LHCb Collaboration – based on the 3 fb −1 data set and on two different experimental analysis methods – still shows some tensions with the Standard Model predictions. We present a detailed analysis of the theoretical inputs and various global fits to all the available b → s l + l − data. This constitutes the first global analysis of the new data of the LHCb Collaboration based on the hypothesis that these tensions can be at least partially explained by new physics contributions. In our model-independent analysis we present one-, two-, four-, and also five-dimensional global fits in the space of Wilson coefficients to all available b → s l + l − data. We also compare the two different experimental LHCb analyses of the angular observables in B → K ⁎ μ + μ − . We explicitly analyse the dependence of our results on the assumptions about power corrections, but also on the errors present in the form factor calculations. Moreover, based on our new global fits we present predictions for ratios of observables which may show a sign of lepton non-universality. Their measurements would crosscheck the LHCb result on the ratio R K = BR ( B + → K + μ + μ − ) / BR ( B + → K + e + e − ) in the low- q 2 region which deviates from the SM prediction by 2.6 σ .

New observables in the decay mode anti-B --> anti-K*0 l+ l-

A bstractThere are some slight tensions with the SM predictions within the latest LHCb measurements. Besides the known anomaly in one angular observable of the rare decay B → K*μ+μ−, another small discrepancy recently occurred. The ratio RK = BR(B+ → K+μ+μ−)/BR(B+ → K+e+e−) in the low-q2 region has been measured by LHCb showing a 2.6σ deviation from the SM prediction. In contrast to the anomaly in the rare decay B → K*μ+μ− which is affected by power corrections, the ratio RK is theoretically rather clean. We analyse all the b → sℓℓ data with global fits and in particular explore the possibility of breaking of lepton universality. Possible cross-checks with an analysis of the inclusive B → Xsℓ+ℓ− decay are also explored.

The minimal flavour violation benchmark in view of the latest LHCb data

A bstractThe latest LHCb angular analysis of the rare decay B → K∗μ+μ− shows some discrepancies from the SM up to the 3.7σ level. There is a consistent new physics explanation of these anomalies, while it is also reasonable that these anomalies are just statistical fluctuations and/or a direct consequence of underestimated hadronic uncertainties. We briefly discuss possible cross-checks of the various hypotheses with an analysis of the inclusive B → Xsℓ+ℓ− based on the data collected by the B factories Babar and Belle and also based on future opportunities at SuperBelle. We also present a global analysis of the latest LHCb data under the hypothesis of Minimal Flavour Violation. The latter is an important benchmark scenario for new physics models. Any measurements beyond the MFV bounds and relations unambiguously indicate the existence of new flavour structures next to the Yukawa couplings of the Standard Model. However, if new physics is responsible for these discrepancies, we show it is compatible with the MFV hypothesis, so no new flavour structures are needed. Moreover, we analyse the impact of the correlations between the observables based on a Monte Carlo study.

Inclusive

We discuss the large set of observables available from the angular distributions of the decay anti-B --> anti-K*0 l+ l-. We present a NLO analysis of all observables based on the QCD factorization approach in the low-dilepton mass region and an estimate of Lambda/m_b corrections. Moreover, we discuss their sensitivity to new physics. We explore the experimental sensitivities at LHCb (10 fb^-1) and Super-LHCb (100 fb^-1) based on a full-angular fit method and explore the sensitivity to right handed currents. We also show that the previously discussed transversity amplitude A_T^(1) cannot be measured at the LHCb experiment or at future B factory experiments as it requires a measurement of the spin of the final state particles.

\overline{B}\to {X}_s{\ell}^{+}{\ell}^{-}

We derive the consequences of the MFV hypothesis for ΔF=1 flavour observables based on the latest LHCb data. Any future measurement beyond the MFV bounds and relations unambiguously indicates the existence of new flavour structures next to the Yukawa couplings of the Standard Model.

: complete angular analysis and a thorough study of collinear photons

A bstractWe investigate logarithmically enhanced electromagnetic corrections of all angular observables in inclusive B¯→Xsℓ+ℓ−