11 pages, 4 figures. Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 2010
This talk gives an overview of correlations between new physics effects in rare B and K decays arising in concrete models or on a model-independent basis and discusses how these correlations can be utilized to distinguish between different classes of new physics scenarios.
The following proceedings contain a theory perspective on rare Kaon decays. I review rare kaon decays in the LHC era: we discuss interplay with B-anomalies and possible New Physics in direct CP violation in $K\to 2π$: very rare kaon decays like $K \to πν\barν$ are very important to this purpose. We discuss also the decays $K^0 \to μ^+ μ^-$ due to the LHCB measurement
I review recent developments in rare and radiative kaon decays from the theory side, with emphasis on those modes that are actively analyzed by the experimental collaborations.
We study rare four-body decays of the Z-boson involving at least one neutrino and one charged lepton. Large destructive interferences make these decays very sensitive to the Z couplings to neutrinos. As the identified charged leptons can determine the neutrino flavors, these decays probe the universality of the Z couplings to neutrinos. The rare four-body processes could be accurately measured at future lepton colliders, leading to percent level precision.
We study (semi)leptonic rare charm decays and its opportunities in searches for physics beyond the Standard Model (BSM). In particular, we analyse the impact of potential BSM physics in $c\to ull'$ transitions, notably branching ratios, angular observables, asymmetries and Lepton Flavour Violating (LFV) decays. Testable effects are worked out model-independently and within Leptoquark models supplemented with flavour patterns to link $K$/$B$ decays.
We consider measurements of exclusive rare semi-tauonic $b$-hadron decays, mediated by the $b \rightarrow s τ^+ τ^-$ transition, at a future high energy circular electron-positron collider (FCC-$ee$). We argue that the high boosts of $b$-hadrons originating from on-shell $Z$ boson decays allow for a full reconstruction of the decay kinematics in hadronic $τ$ decay modes (up to discrete ambiguities). This, together with the potentially large statistics of $Z\to b\bar b$, opens the door for the experimental determination of $τ$ polarizations in these rare $b$-hadron decays. In light of the curre…
Analysis of rare (B -> K_0*(1430) l^+ l^- decay) within QCD sum rules
B -> K_0 ~*(1430)1 ^+1 ^- $ decay) decay are calculated within three-point QCD sum rules, with (K_0* (1430)) being the p-wave scalar meson. The branching ratios are estimated when only short, as well as short and long distance effects, are taken into account.It is obtained that the (B -> K_0*(1430) l^+ l^- (l=e,mu)) decay is measurable at LHC. Measurement of these branching ratios for the semileptonic rare (B -> K_0*(1430) l^+ l^-$衰变的形状因子可以提供有关标量介子(K_0 ~*(1430))性质的有价值的信息。
An analysis of charm mesons decaying semileptonically via Flavor Changing Neutral Currents is presented. We calculate the Wilson coefficients within the Standard Model. A window in the decay distribution, where physics beyond the Standard Model could be measured is identified. Exemplary, we study effects of leptoquark models.
Motivated by the recent measurement of $D^0\toρ^0γ$ improved standard model (SM) predictions for branching ratios and CP asymmetries of radiative charm decay are given. Weak annihilation induced decays are probes of non-perturbative QCD approaches. Rare decays probe the SM and physics beyond the SM, e.g. leptoquark and supersymmetric models. Opportunities with $Λ_c\to pγ$ for future polarization measurements are presented.