Key points are not available for this paper at this time.
Abstract The observed flavor-changing neutral-current (FCNC) processes in the standard model (SM) arise from the loop diagrams involving the weak charged currents mediated by the W-gauge boson. Nevertheless, the top-quark FCNCs and lepton flavor-violating processes resulting from the same mechanism are highly suppressed. We investigate possible new physics effects that can enhance the suppressed FCNC processes, such as a top quark decaying into a light quark with a Higgs or gauge boson in the final state, i. e. , t q (h, V) with V=, Z, g, h ', and '. To achieve the assumption that the induced FCNCs are all from quantum loops, we consider the scotogenic mechanism, where a Z₂ symmetry is introduced and only new particles carry an odd Z₂ parity. With the extension of the SM to include an inert Higgs doublet, an inert charged Higgs singlet, a vector-like singlet quark, and two neutral leptons, it is found that, with relevant constraints taken into account, the t c (h, Z), h, and decays can be enhanced up to the expected sensitivities in experiments. The branching ratios of h ^+ ^-/^+ ^- from only new physics effects can reach up to O (10^-3). Intriguingly, the resulting muon g-2 can fit the combined data within 2 standard deviations, whereas the electron g-2 can have either sign with a magnitude of O (10^-13-10^-12). In addition, we examine the oblique parameters in the model and find that the resulting W-mass anomaly observed by CDF II can be accommodated.
Chen et al. (Mon,) studied this question.