Related papers: The GIM Mechanism: origin, predictions and recent …
The small neutrino mass observed in neutrino oscillations is nicely explained by the seesaw mechanism. Rich phenomenology is generally expected if the heavy neutrinos are not much heavier than the electroweak scale. A model with this…
In the framework of the Standard Model Effective Field Theory, we compare the lower bounds on the scale of new physics possibly contributing to the $f\bar{f}h$ effective couplings, obtained from the measurements of different observables,…
We perform a systematic reevaluation of the constraints on the flavor-changing neutral current (FCNC) parameters in R-parity conserving and R-parity violating supersymmetric models. As a typical process, we study the constraints coming from…
We compare theoretical and experimental predictions of two main classes of models addressing fermion mass hierarchies and flavour changing neutral currents (FCNC) effects in supersymmetry: Froggatt-Nielsen (FN) U(1) gauged flavour models…
The biologist Ren\'e Thomas conjectured, twenty years ago, that the presence of a negative feedback circuit in the interaction graph of a dynamical system is a necessary condition for this system to produce sustained oscillations. In this…
I review recent progress in theoretical calculations related to the CKM unitarity triangle. After briefly discussing hints for new physics in B_d-B_d-bar mixing and B_s-B_s-bar mixing I present three topics of MSSM flavor physics: First I…
The Effective Field Theory (EFT) approach is widely used in the search for possible deviations from the predictions of the Standard Model. Such an approximation of possible BSM physics is valid up to a certain levels of energy scale and…
In many extensions of the Standard Model flavour changing neutral current processes can be mediated by tree-level heavy neutral scalars and/or pseudo-scalars H^0(A^0). This generally introduces new sources of flavour violation and CP…
We investigate a framework of the Minimal Supersymmetric Standard Model (MSSM) in which the quark and lepton flavor structure and suppression of flavor-changing neutral currents (FCNCs) are governed by non-invertible selection rules. By…
In the $SO(5) \times U(1) \times SU(3)$ gauge-Higgs unification in the Randall-Sundrum warped space the mixing in the $W$ couplings in the quark sector is induced by masses of $SO(5)$ singlet fermions which are responsible for splitting…
Flavor-changing neutral current (FCNC) top-quark decays are highly suppressed due to the Glashow-Iliopoulos-Maiani mechanism in the standard model (SM). If $t\to q h, qV$ with $V=g,\gamma, Z$ are all induced via quantum loop levels, then we…
We investigate forces induced by the exchange of two light neutrinos between Standard Model (SM) fermions in the presence of effective operators parametrising physics beyond the SM. We first set up a general framework in which we derive the…
The simplest extension of the SM that generally introduces new sources of flavour and CP violation as well as right-handed currents is the addition of a U(1) gauge symmetry to the SM gauge group. If the corresponding heavy gauge boson Z'…
We analyse $Z^\prime$ contributions to FCNC processes at the one-loop level. In analogy to the CKM matrix we introduce two $3\times3$ unitary matrices $\hat\Delta_d(Z^\prime)$ and $\hat\Delta_u(Z^\prime)$ which are also hermitian. They…
In this work, we compile the necessary and sufficient conditions a theory has to fulfill in order to ensure general lepton flavour conservation, in the spirit of the Glashow-Weinberg criteria for the absence of flavour-changing neutral…
The LHC will have unprecedented sensitivity to flavor-changing neutral current (FCNC) top quark decays, whose observation would be a clear sign of physics beyond the standard model. Although many details of top flavor violation are model…
It is pointed out that in a general class of flavour models one can identify certain universally present FCNC operators, induced by the exchange of heavy flavour messengers. Their coefficients depend on the rotation angles that connect…
The field-cooled (FC) process on an Ising spin-glass model is investigated by a standard Monte Calro (MC) method on one hand, and the equilibrium magnetization of the same system is evaluated by the exchang MC method on the other hand. The…
We consider the problem of predicting perturbation effects via causal models. In many applications, it is a priori unknown which mechanisms of a system are modified by an external perturbation, even though the features of the perturbation…
The rates of the rare flavor-changing processes, $b \rightarrow s \gamma$ and $B_s \rightarrow \mu^+ \mu^-$ are estimated in extended technicolor models with and without a GIM mechanism. We find the $b \rightarrow s \gamma$ rate in ETC…