Related papers: Constraints on exotic lepton doublets with minimal…
By introducing a set of new triplet leptons (with nonzero hypercharge) that can Yukawa couple to their Standard Model counterparts, new sources of tree-level flavor changing currents are induced via mixing. In this work, we study some of…
The extension of the Standard Model with exotic quark singlets and doublets introduces large flavor changing neutral couplings between ordinary fermions. We derive inequalities which translate the precise determination of the diagonal Z…
Together with any Beyond the Standard Model ultraviolet complete, renormalizable model, one or several exotic particles are usually hypothesized. $C\!P$-even neutral and doubly-charged scalars are common, well known examples which can…
The constraints on the mixing angles of the standard fermions with new heavy particles that can appear in many extensions of the electroweak theory are reviewed. Some emphasis is put in distinguishing the effects of a mixing with new states…
New neutral heavy gauge bosons ($Z^\prime$) are predicted within many extensions of the Standard Model. While in case they couple to quarks the LHC bounds are very stringent, leptophilic $Z^\prime$ bosons (even with sizable couplings) can…
Gauged extensions [$SU(2)_L\otimes U(1)_Y\otimes U(1)_X$] of the standard $SU(2)_L\otimes U(1)_Y$ model obtained without extending the fermion content of the model are studied. Models that are possible when $U(1)_X$ is identified with some…
In light of the ongoing effort on reducing the theoretical uncertainties and an upcoming experiment concerning muon magnetic moment, we perform a detailed study of an 3-4-1 electroweak gauge extension of the standard model that contains…
We explore constraints on the parameter space of the alternative left-right model originating from the leptonic sector. Our analyses focuses on both lepton-flavour-conserving observables, particularly the anomalous magnetic moment of the…
Lepton flavor violating processes are obtained from the mixing between ordinary leptons and vectorlike SU(2)_L doublet leptons which may originate in E_6. The effects of this lepton mixing are, however, suppressed naturally by the hierarchy…
The anomalous magnetic moment of a lepton encodes the fraction of the lepton's interaction strength with an external magnetic field, which is generated by quantum corrections. Lepton anomalous magnetic moments are sensitive probes of…
The most general phenomenological model involving a lepton triplet with hypercharge $\pm 1$ is constructed. A distinctive feature of this model is the prediction of a doubly charged lepton, and a new heavy Dirac neutrino. We study the…
The results of various searches for new physical phenomena beyond the Standard Model using data from the four LEP experiments are summarized. Topics presented include the search for flavour-changing neutral currents with single top…
The measurements of rare leptonic and semi-leptonic B decays performed at the LHC, not showing any significant deviations from the Standard Model expectations, put strong constraints on new physics. A brief account of the impact of recent…
Lepton flavor violated processes are strongly suppressed in the Standard Model, but can be sizable in some extended models. The current experimental bounds on decay modes $\ell'^{\pm} \to a \ell^{\pm}$ are much weaker than the other…
The leptonic branching fractions of the tau lepton are sensitive to anomalous charged current interactions. We use recent experimental measurements to determine the weak charged current magnetic and electric dipole moments and the Michel…
A non-universal interaction, which involves only the third family leptons induces lepton flavor violating couplings and contributes to the anomalous magnetic moment of muon. In this paper, we study the effects of non-universal interaction…
In a two Higgs doublet model with extra Yukawa couplings, we assess the new physics contributions to charged lepton electric dipole moment. We focus especially on muon (and tau) EDM where in the coming decade several experiments $-$ Muon…
The fact that the measured B to \pi \pi, \pi K branching ratios exhibit puzzling patterns has received a lot of attention in the literature and motivated the formulation of a series of new physics scenarios with enhanced Z-penguins. In this…
We explore a Z' boson with family-nonuniversal couplings to charged leptons. The general effect of Z-Z' mixing, of both kinetic and mass types, is included in the analysis. Adopting a model-independent approach, we perform a comprehensive…
We study extensions of the standard model by one generation of vector-like leptons with non-standard hypercharges, which allow for a sizable modification of the h -> gamma gamma decay rate for new lepton masses in the 300 GeV - 1 TeV range.…