71 research outputs found
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 and 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 , between
the scalar and pseudoscalar component of the 125 GeV Higgs, in the decay will be able to probe many of these scenarios, even with low
luminosity. Similarly, a measurement of in the vertex
could help to constrain the low 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 is evaluated at one loop in a general 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 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 , ,
, , , and in an extension of the Standard Model having arbitrary
numbers of singlet, doublet, and triplet quarks with electric charges ,
, , and 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 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 , , and the decay of a heavy charged scalar into a lighter one and a
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
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