Related papers: Flavor Changing Neutral Currents in the Lee-Wick S…
It is possible that the standard model (SM) is replaced around some transition energy $\E_{tr}$ by a new, possibly Higgsless, ``flavor gauge theory'' such that the Yukawa (running) parameters of SM at $E \sim \E_{tr}$ show up an…
Flavor changing neutral currents coming from a new non-universal neutral Gauge-Boson and from the non-unitary quark mixing matrix for the $SU(3)_c\otimes SU(3)_L\otimes U(1)_X$ model with right handed neutrinos are studied. By imposing as…
Models with a non-universal Z' exhibit in general flavor changing neutral currents (FCNC) at tree-level. When the Z' couplings favor the third generation, flavor changing transitions of the form Z'tc and Z'tu could be large enough to be…
A discrete symmetry between quarks and (generalized) leptons can exist in nature, and its spontaneous symmetry breaking scale can be as low as a few TeV. Such a discrete symmetry also has interesting implications for how electroweak…
Dark, chiral fermions carrying lepton flavor quantum numbers are natural candidates for freeze-in. Small couplings with the Standard Model fermions of the order of lepton Yukawas are `automatic' in the limit of Minimal Flavor Violation. In…
Leptophobic Z' gauge bosons can appear in models with an E_6 gauge symmetry. We show that flavour-changing neutral currents can be generated in some of these models due to the mixing of the ordinary d_R, s_R and b_R quark fields with the…
In the lepton-specific version of two Higgs doublet models, a discrete symmetry is used to couple one Higgs, $\Phi_2$, to quarks and the other, $\Phi_1$, to leptons. The symmetry eliminates tree level flavor changing neutral currents…
The loop level flavor changing neutral currents transitions of the $\Sigma_{b}\to n l^+l^-$ and $\Sigma_{c}\to p l^+l^-$ are investigated in full QCD and heavy quark effective theory in the light cone QCD sum rules approach. Using the most…
Uniquely heavy with mass at the weak scale, the top quark may have large flavor changing couplings to Higgs bosons that are as yet unexplored. We show that such couplings can be directly probed at the LHC through the parton subprocess…
We analise phenomenological implications of two Higgs doublet models with Higgs flavour changing neutral currents suppressed in the quark sector by small entries of the Cabibbo-Kokayashi-Maskawa matrix. This suppression occurs in a natural…
We examine the constraints coming from incorporating the full Standard Model gauge symmetry into the effective field theory description of flavor processes, using semileptonic decays as paradigmatic examples. Depending on the dynamics…
We propose a Three Higgs Doublet Model (3HDM) that goes beyond natural flavor conservation and in which each of the three Higgs doublets couples mainly to a single generation of fermions via non-standard Yukawa structures. A hierarchy in…
We analyze the prospect for observing the lightest and heaviest CP-even neutral Higgs bosons ($\phi=h,\;H$) in their decays to flavor violating $b\bar{s}$ (with charge conjugate) final states at the future Large Hadron electron Collider…
We investigate the deviation in the couplings of the standard model (SM) like Higgs boson ($h$) with a mass of 125 GeV from the prediction of the SM in multi-doublet models within the framework where flavour changing neutral currents at the…
We reconsider the flavor problem in the models with two Higgs doublets. By studying two generation toy models, we look for flavor basis independent constraints on Yukawa couplings that will give us the mass hierarchy while keeping all…
We carry out a general analysis of tree level flavor changing neutral currents in the context of 331 models, considering arbitrary quark and gauge boson mixing matrices. The results are applied to definite textures of quark mass matrices,…
Small neutrino masses can arise in some grand unified models or superstring theories. We consider a model with an enhanced fermion sector containing Dirac neutral heavy leptons. The dependence on the mass and mixing parameters of these new…
We study a new class of flavor changing interactions, which can arise in models based on extended gauge groups (rank $>$4) when new charged fermions are present together with a new neutral gauge boson. We discuss the cases in which the…
We study a simple extension of the Zee model, in which a discrete $Z_2$ symmetry imposed in the original model is replaced by a global $U(1)$ symmetry retaining the same particle content. Due to the $U(1)$ symmetry with flavor dependent…
The reactions e+e- -> t bar-c nu_e bar-nu_e, t bar-c e+ e- are very sensitive probes of the flavor-changing-scalar couplings which can occur in a model with one extra Higgs doublet. At the Next Linear Collider, with a center of mass energy…