Botella, F. J., Cornet-Gomez, F., & Nebot, M. (2018). Flavor conservation in two-Higgs-doublet models. Phys. Rev. D, 98(3), 035046–25pp.
Abstract: In extensions of the Standard Model with two Higgs doublets, flavor-changing Yukawa couplings of the neutral scalars may be present at tree level. In this work, we consider the most general scenario in which those flavor-changing couplings are absent. We revise the conditions that the Yukawa coupling matrices must obey for such general flavour conservation (gFC) and study the one-loop renormalization group evolution of such conditions in both the quark and lepton sectors. We show that gFC in the leptonic sector is one-loop stable under the renormalization group evolution, and in the quark sector, we present some new Cabibbo-like solution also one-loop stable under renormalization group evolution. At a phenomenological level, we obtain the regions for the different gFC parameters that are allowed by the existing experimental constraints related to the 125 GeV Higgs.
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Alves, J. M., Botella, F. J., Branco, G. C., Cornet-Gomez, F., & Nebot, M. (2017). Controlled flavour changing neutral couplings in two Higgs Doublet models. Eur. Phys. J. C, 77(9), 585–18pp.
Abstract: We propose a class of two Higgs doublet models where there are flavour changing neutral currents (FCNC) at tree level, but under control due to the introduction of a discrete symmetry in the full Lagrangian. It is shown that in this class of models, one can have simultaneously FCNC in the up and down sectors, in contrast to the situation encountered in the renormalisable and minimal flavour violating 2HDM models put forward by Branco et al. (Phys Lett B 380: 119, 1996). The intensity of FCNC is analysed and it is shown that in this class of models one can respect all the strong constraints from experiment without unnatural fine-tuning. It is pointed out that the additional sources of flavour and CP violation are such that they can enhance significantly the generation of the Bbaryon asymmetry of the Universe, with respect to the standard model.
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