2,209 research outputs found
Multi-Higgs models with CP symmetries of increasingly high order
When building CP-symmetric models beyond the Standard Model, one can impose
CP-symmetry of higher order. This means that one needs to apply the
CP-transformation more than two times to get the identity transformation, but
still the model is perfectly CP-conserving. A multi-Higgs-doublet model based
on CP-symmetry of order 4, dubbed CP4, was recently proposed and its
phenomenology is being explored. Here, we show that the construction does not
stop at CP4. We build examples of renormalizable multi-Higgs-doublet potentials
which are symmetric under CP8 or CP16, without leading to any accidental
symmetry. If the vacuum conserves CP-symmetry of order 2k, then the neutral
scalars become CP-eigenstates, which are characterized not by CP-parities but
by CP-charges defined modulo 2k. One or more lightest states can be the dark
matter candidates, which are protected against decay not by the internal
symmetry but by the exotic CP. We briefly discuss their mass spectra and
interaction patterns for CP8 and CP16.Comment: 13 pages; v2: extra comments and references; v3: extra
clarifications, matches published versio
Beyond basis invariants
Physical observables cannot depend on the basis one chooses to describe
fields. Therefore, all physically relevant properties of a model are, in
principle, expressible in terms of basis-invariant combinations of the
parameters. However, in many cases it becomes prohibitively difficult to
establish key physical features exclusively in terms of basis invariants. Here,
we advocate an alternative route in such cases: the formulation of
basis-invariant statements in terms of basis-covariant objects. We give several
examples where the basis-covariant path is superior to the traditional approach
in terms of basis invariants. In particular, this includes the formulation of
necessary and sufficient basis-invariant conditions for various physically
distinct forms of CP conservation in two- and three-Higgs-doublet models.Comment: 20 pages, no figure
CP4 miracle: shaping Yukawa sector with CP symmetry of order four
We explore the phenomenology of a unique three-Higgs-doublet model based on
the single CP symmetry of order 4 (CP4) without any accidental symmetries. The
CP4 symmetry is imposed on the scalar potential and Yukawa interactions,
strongly shaping both sectors of the model and leading to a very characteristic
phenomenology. The scalar sector is analyzed in detail, and in the Yukawa
sector we list all possible CP4-symmetric structures which do not run into
immediate conflict with experiment, namely, do not lead to massless or
mass-degenerate quarks nor to insufficient mixing or CP-violation in the CKM
matrix. We show that the parameter space of the model, although very
constrained by CP4, is large enough to comply with the electroweak precision
data and the LHC results for the 125 GeV Higgs boson phenomenology, as well as
to perfectly reproduce all fermion masses, mixing, and CP violation. Despite
the presence of flavor changing neutral currents mediated by heavy Higgs
scalars, we find through a parameter space scan many points which accurately
reproduce the kaon CP-violating parameter as well as oscillation
parameters in K and mesons. Thus, CP4 offers a novel minimalistic
framework for building models with very few assumptions, sufficient predictive
power, and rich phenomenology yet to be explored.Comment: 39 pages, 8 figures, 1 table; v2: expanded discussion, extra
references, matches published versio
Dark matter from CP symmetry of order 4: evolution in the asymmetric regime
Multi-Higgs models equipped with global symmetries produce scalar dark matter
(DM) candidates stabilized by the unbroken symmetry. It is remarkable that a
conserved CP symmetry can also stabilize DM candidates, provided it is a CP
symmetry of order higher than two. CP4 3HDM, the three-Higgs-doublet model with
CP symmetry of order 4, is the simplest example of this kind. It contains two
mass-degenerate scalar DM candidates and , each of them
being a CP4 eigenstate and, therefore, its own antiparticle. A novel
phenomenological feature of this model is the presence of conversion process, which conserves CP.
It offers a rare example of DM models in which self-interaction in the dark
sector can significantly affect cosmological and astrophysical observables.
Here, we explore the thermal evolution of these DM species in the asymmetric
regime. We assume that a mechanism external to CP4 3HDM produces an initial
imbalance of the densities of and . As the Universe
cools down, we track the evolution of the asymmetry through different stages,
and determine how the final asymmetry depends on the interplay between the
conversion and annihilation SM and on the initial
conditions. We begin with the analytic treatment of Boltzmann equations,
present a detailed qualitative description of the process, and then corroborate
it with numerical results obtained using a dedicated computer code. Finally, we
check if the model can produce an observable indirect detection signal.Comment: 17 pages, 4 figure
Symmetries for the 4HDM: extensions of cyclic groups
Multi-Higgs models equipped with global symmetry groups, either exact or
softly broken, offer a rich framework for constructions beyond the Standard
Model and lead to remarkable phenomenological consequences. Knowing all the
symmetry options within each class of models can guide its phenomenological
exploration, as confirmed by the vast literature on the two- and
three-Higgs-doublet models. Here, we begin a systematic study of finite
non-abelian symmetry groups which can be imposed on the scalar sector of the
four-Higgs-doublet model (4HDM) without leading to accidental symmetries. In
this work, we derive the full list of such non-abelian groups available in the
4HDM that can be constructed as extensions of cyclic groups by their
automorphism groups. This list is remarkably restricted but it contains cases
which have not been previously studied. Since the methods we develop may prove
useful for other classes of models, we present them in a pedagogical manner.Comment: v2: 36 pages, 2 tables, additional clarifications, matches the
published versio
Inclusive One Jet Production With Multiple Interactions in the Regge Limit of pQCD
DIS on a two nucleon system in the regge limit is considered. In this
framework a review is given of a pQCD approach for the computation of the
corrections to the inclusive one jet production cross section at finite number
of colors and discuss the general results.Comment: 4 pages, latex, aicproc format, Contribution to the proceedings of
"Diffraction 2008", 9-14 Sep. 2008, La Londe-les-Maures, Franc
Frustrated symmetries in multi-Higgs-doublet models
Within multi-Higgs-doublet models, one can impose symmetries on the Higgs
potential, either discrete or continuous, that mix several doublets. In
two-Higgs-doublet model any such symmetry can be conserved or spontaneously
violated after the electroweak symmetry breaking (EWSB), depending on the
coefficients of the potential. With more than two doublets, there exist
symmetries which are always spontaneously violated after EWSB. We discuss the
origin of this phenomenon and show its similarity to geometric frustration in
condensed-matter physics.Comment: 7 pages, no figure
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