Large pseudoscalar Yukawa couplings in the complex 2HDM

We start by presenting the current status of a complex flavour conserving two-Higgs doublet model. We will focus on some very interesting scenarios where unexpectedly the light Higgs couplings to leptons and to b-quarks can have a large pseudoscalar component with a vanishing scalar component. Predictions for the allowed parameter space at end of the next run with a total collected luminosity of $300 \, fb^{-1}$ and $3000 \, fb^{-1}$ are also discussed. These scenarios are not excluded by present data and most probably will survive the next LHC run. However, a measurement of the mixing angle $\phi_\tau$, between the scalar and pseudoscalar component of the 125 GeV Higgs, in the decay $h \to \tau^+ \tau^-$ will be able to probe many of these scenarios, even with low luminosity. Similarly, a measurement of $\phi_t$ in the vertex $\bar t t h$ could help to constrain the low $\tan \beta$ region in the Type I model.Comment: 21 pages, 10 figure

CP violation in 2HDM and EFT: the ZZZ vertex

We study the CP violating ZZZ vertex in the two-Higgs doublet model, which is a probe of a Jarlskog-type invariant in the extended Higgs sector. The form factor $f_4^Z$ is evaluated at one loop in a general $R_\xi$ gauge and its magnitude is estimated in the realistic parameter space. Then we turn to the decoupling limit of the two-Higgs doublet model, where the extra scalars are heavy and the physics can be described by the Standard Model supplemented by higher-dimensional operators. The leading operator contributing to $f_4^Z$ at one loop is identified. The CP violating ZZZ vertex is not generated in the effective theory by dimension-8 operators, but instead arises only at the dimension-12 level, which implies an additional suppression by powers of the heavy Higgs mass scale.Comment: 21 pages; v2: added references and comments, appendix A on method of regions, and appendix B on derivation of CP-violating effective Lagrangian. Corrected discussion of dimension-12 operators contributing to ZZZ vertex. Final JHEP versio

Oblique corrections from triplet quarks

We present general formulas for the oblique-correction parameters $S$, $T$, $U$, $V$, $W$, and $X$ in an extension of the Standard Model having arbitrary numbers of singlet, doublet, and triplet quarks with electric charges $-4/3$, $-1/3$, $2/3$, and $5/3$ that mix with the standard quarks of the same charge.Comment: 30 page

BFB conditions on a class of symmetry constrained 3HDM

We study the bounded from below (BFB) conditions on a class of three Higgs doublet models (3HDM) constrained by the symmetry groups U(1)xU(1), U(1)xZ2 and Z2xZ2. These constraints must be implemented on both the neutral (BFB-n) and charged (BFB-c) directions. The exact necessary and sufficient BFB conditions are unknown in the Z2xZ2 case. We develop a general strategy using lower bounds to find sufficient conditions for BFB-n and BFB-c and apply it to these symmetries. In addition, we investigate the concern that the use of safe sufficient conditions can ignore valid points which would yield distinct physical consequences. This is done by performing a full phenomenological simulation of the U(1)xU(1) and U(1)xZ2 models, where exact necessary and sufficient BFB conditions are possible. We look specifically at the points allowed by exact solutions but precluded by safe lower bounds. We found no evidence of remarkable new effects, partly reassuring the use of the lower bounds we propose here, for those potentials where no exact necessary and sufficient BFB conditions are known.Comment: 41 pages, 15 Figures, revtex. arXiv admin note: text overlap with arXiv:2106.1197

Off diagonal charged scalar couplings with the Z boson: the Zee model as an example

Models with scalar doublets and charged scalar singlets have the interesting property that they have couplings between one $Z$ boson and two charged scalars of different masses. This property is often ignored in phenomenological analysis, as it is absent from models with only extra scalar doublets. We explore this issue in detail, considering $h \rightarrow Z \gamma$, $B \to X_s \gamma$, and the decay of a heavy charged scalar into a lighter one and a $Z$ boson. We propose that the latter be actively searched for at the LHC, using the scalar sector of the Zee model as a prototype and proposing benchmark points which obey all current experimental data and could be within reach of the LHC.Comment: 40 pages, 28 Figures in PD