TUM Institute for Advanced Study

About: TUM Institute for Advanced Study is a based out in . It is known for research contribution in the topics: CP violation & Physics beyond the Standard Model. The organization has 67 authors who have published 131 publications receiving 5827 citations. The organization is also known as: Institute for Advanced Study & IAS.

Symmetries and Asymmetries of B -> K* mu+ mu- Decays in the Standard Model and Beyond

Abstract: 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.

$$ B\to {K}^{\left(\ast \right)}\nu \overline{\nu} $$ decays in the Standard Model and beyond

Abstract: We present an analysis of the rare exclusive B decays $$ B\to K u \overline{ u} $$ and $$ B\to {K}^{\ast} u \overline{ u} $$ within the Standard Model (SM), in a model-independent manner, and in a number of new physics (NP) models. Combining new form factor determinations from lattice QCD with light-cone sum rule results and including complete two-loop electroweak corrections to the SM Wilson coefficient, we obtain the SM predictions $$ \mathrm{B}\mathrm{R}\left({B}^{+}\to {K}^{+} u \overline{ u}\right)=\left(4.0\pm 0.5\right)\times 1{0}^{-6} $$ and $$ \mathrm{B}\mathrm{R}\left({B}^0\to {K}^{\ast 0} u \overline{ u}\right)=\left(9.2\pm 1.0\right)\times 1{0}^{-6} $$ , more precise and more robust than previous estimates. Beyond the SM, we make use of an effective theory with dimension-six operators invariant under the SM gauge symmetries to relate NP effects in $$ b\to s u \overline{ u} $$ transitions to b → sl + l − transitions and use the wealth of experimental data on B → K (∗) l + l − and related modes to constrain NP effects in $$ B\to {K}^{\left(\ast \right)} u \overline{ u} $$ . We then consider several specific NP models, including Z′ models, the MSSM, models with partial compositeness, and leptoquark models, demonstrating that the correlations between $$ b\to s u \overline{ u} $$ observables among themselves and with B s → μ + μ − and b → sl + l − transitions offer powerful tests of NP with new right-handed couplings and non-MFV interactions.

K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ and K L → π 0 ν ν ¯ $$ {K}_L\to {\pi}^0\nu \overline{\nu} $$ in the Standard Model: status and perspectives

Abstract: In view of the recent start of the NA62 experiment at CERN that is expected to measure the $$ {K}^{+}\to {\pi}^{+} u \overline{ u} $$ branching ratio with a precision of 10%, we summarise the present status of this promising decay within the Standard Model (SM). We do likewise for the closely related $$ {K}_L\to {\pi}^0 u \overline{ u} $$ , which will be measured by the KOTO experiment around 2020. As the perturbative QCD and electroweak corrections in both decays are under full control, the dominant uncertainties within the SM presently originate from the CKM parameters |V cb |, |V ub | and γ. We show this dependence with the help of analytic expressions as well as accurate interpolating formulae. Unfortunately a clarification of the discrepancies between inclusive and exclusive determinations of |V cb | and |V ub | from tree-level decays will likely require results from the Belle II experiment available at the end of this decade. Thus we investigate whether higher precision on both branching ratios is achievable by determining |V cb |, |V ub | and γ by means of other observables that are already precisely measured. In this context e K and ΔM s,d , together with the expected progress in QCD lattice calculations will play a prominent role. We find $$ \mathrm{\mathcal{B}}\left({K}^{+}\to {\pi}^{+} u \overline{ u}\right)=\left(9.11 \pm 0.72\right) \times 1{0}^{-11} $$ and $$ \mathrm{\mathcal{B}}\left({K}_L\to {\pi}^0 u \overline{ u}\right)\Big) = \left(3.00 \pm 0.30\right) \times 1{0}^{-11} $$ , which is more precise than using averages of the present tree-level values of |V cb |, |V ub | and γ. Furthermore, we point out the correlation between $$ \mathrm{\mathcal{B}}\left({K}^{+}\to {\pi}^{+} u \overline{ u}\right),\ \overline{\mathrm{\mathcal{B}}}\left({B}_{\mathrm{s}}\to {\mu}^{+}{\mu}^{-}\right) $$ and γ within the SM, that is only very weakly dependent on other CKM parameters. Finally, we update the correlation of $$ {K}_L\to {\pi}^0 u \overline{ u} $$ with the ratio e′ /e in the SM taking the recent progress on e′ /e from lattice QCD and the large N approach into account.