34,158 research outputs found
Physical parameters and basis transformations in the Two-Higgs-Doublet model
A direct connection between physical parameters of general Two-Higgs-Doublet
Model (2HDM) potentials after electroweak symmetry breaking (EWSB) and the
parameters that define the potentials before EWSB is established. These
physical parameters, such as the mass matrix of the neutral Higgs bosons, have
well defined transformation properties under basis transformations transposed
to the fields after EWSB. The relations are also explicitly written in a basis
covariant form. Violation of these relations may indicate models beyond 2HDMs.
In certain cases the whole potential can be defined in terms of the physical
parameters. The distinction between basis transformations and
reparametrizations is pointed out. Some physical implications are discussed.Comment: 11 pages. 1 figure. v2: references and comments adde
Discrete and continuous symmetries in multi-Higgs-doublet models
We consider the Higgs sector of multi-Higgs-doublet models in the presence of
simple symmetries relating the various fields. We construct basis invariant
observables which may in principle be used to detect these symmetries for any
number of doublets. A categorization of the symmetries into classes is
required, which we perform in detail for the case of two and three Higgs
doublets.Comment: 13 pages, RevTex, references adde
Structure of potentials with Higgs doublets
Extensions of the Standard Model with Higgs doublets are simple
extensions presenting a rich mathematical structure. An underlying Minkowski
structure emerges from the study of both variable space and parameter space.
The former can be completely parametrized in terms of two future lightlike
Minkowski vectors with spatial parts forming an angle whose cosine is
. For the parameter space, the Minkowski parametrization enables
one to impose sufficient conditions for bounded below potentials, characterize
certain classes of local minima and distinguish charge breaking vacua from
neutral vacua. A particular class of neutral minima presents a degenerate mass
spectrum for the physical charged Higgs bosons.Comment: 11 pages. Revtex4. Typos corrected. Few comments adde
Minkowski space structure of the Higgs potential in 2HDM: II. Minima, symmetries, and topology
We continue to explore the consequences of the recently discovered Minkowski
space structure of the Higgs potential in the two-Higgs-doublet model. Here, we
focus on the vacuum properties. The search for extrema of the Higgs potential
is reformulated in terms of 3-quadrics in the 3+1-dimensional Minkowski space.
We prove that 2HDM cannot have more than two local minima in the orbit space
and that a twice-degenerate minimum can arise only via spontaneous violation of
a discrete symmetry of the Higgs potential. Investigating topology of the
3-quadrics, we give concise criteria for existence of non-contractible paths in
the Higgs orbit space. We also study explicit symmetries of the Higgs
potential/lagrangian and their spontaneous violation from a wider perspective
than usual.Comment: 27 pages, 5 figure
Charge breaking bounds in the Zee model
We study the possibility that charge breaking minima occur in the Zee model.
We reach very different conclusions from those attained in simpler, two Higgs
doublet models, and the reason for this is traced back to the existence of
cubic terms in the potential. A scan of the Zee model's parameter space shows
that CB is restricted to a narrow region of values of the parameters
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