3,085 research outputs found
Phase transition in a supersymmetric axion model
In a supersymmetric axion model where the scale for both supersymmetry
breaking and Peccei-Quinn symmetry breaking is around GeV, we find
that there is a reasonable parameter space for a strongly first order phase
transition at the scale.Comment: 5 pages, 1 figur
Electroweak phase transition in the MSSM with four generations
By assuming the existence of the sequential fourth generation to the minimal
supersymmetric standard model (MSSM), we study the possibility of a strongly
first-order electroweak phase transition. We find that there is a parameter
region of the MSSM where the electroweak phase transition is strongly first
order. In that parameter region, the mass of the lighter scalar Higgs boson is
calculated to be above the experimental lower bound, and the scalar quarks of
the third and the fourth generations are heavier than the corresponding quarks.Comment: 12 pages, 2 tables, 2 figure
Electroweak phase transition in a nonminimal supersymmetric model
The Higgs potential of the minimal nonminimal supersymmetric standard model
(MNMSSM) is investigated within the context of electroweak phase transition. We
investigate the allowed parameter space yielding correct electroweak phase
transitoin employing a high temperature approximation. We devote to
phenomenological consequences for the Higgs sector of the MNMSSM for
electron-positron colliders. It is observed that a future linear
collider with GeV will be able to test the model with regard
to electroweak baryogenesis.Comment: 28 pages, 5 tables, 12 figure
Explicit CP violation in the Dine-Seiberg-Thomas model
The possibility of explicit CP violation is studied in a supersymmetric model
proposed by Dine, Seiberg, and Thomas, with two effective dimension-five
operators. The explicit CP violation may be triggered by complex phases in the
coefficients for the dimension-five operators in the Higgs potential, and by a
complex phase in the scalar top quark masses. Although the scenario of explicit
CP violation is found to be inconsistent with the experimental data at LEP2 at
the tree level, it may be possible at the one-loop level. For a reasonable
parameter space, the masses of the neutral Higgs bosons and their couplings to
a pair of bosons are consistent with the LEP2 data, at the one-loop level.Comment: 5 pages, 2 figure
The Constraints on CP Violating Phases in models with a dynamical gluino phase
We have analyzed the electric dipole moment and the Higgs mass constraints on
the supersymmetric model which offers dynamical solutions to the \mu and strong
CP problems. The trilinear coupling phases, and \tan\beta-|\mu| are strongly
correlated, particularly in the low-\tan\beta regime. Certain values of the
phases of the trilinear couplings are forbidden, whereas the CP violating phase
from the chargino sector is imprisoned to lie near a CP conserving point, by
the Higgs mass and electric dipole moment constraints.Comment: 19 pages, 11 eps fig
The CP properties of the lightest Higgs boson with sbottom effects
In the framework of the recently proposed gluino-axion model, using the
effective potential method and taking into account the top-stop as well as the
bottom-sbottom effects, we discuss the CP--properties of the lightest Higgs
boson, in particular its CP--odd composition, which can offer new opportunities
at collider searches. It is found that although the CP-odd composition of the
lightest Higgs increases slightly with the inclusion of the sbottom effects, it
never exceeds %0.17 for all values of the renormalization scale Q ranging from
top mass to TeV scaleComment: 24 pp, 12 eps fig
Spontaneous Violation of the CP Symmetry in the Higgs Sector of the Next-to-Minimal Supersymmetric Model
The spontaneous violation of the CP symmetry in the next-to-minimal
supersymmetric standard Model (NMSSM) is investigated. It is found that the
spontaneous violation of the CP symmetry can occur in the Higgs sector of the
NMSSM for a wide region of the parameter space of the model, at the 1-loop
level where the radiative corrections due to the top quark and scalar-top quark
loops are found to generate the scalar-pseudoscalar mixings between the two
Higgs doublets of the NMSSM. In our model, we assume that the masses of the
left-handed and the right-handed scalar-top quarks are not degenerate. And we
investigate our model anaytically: We derive analytical formulae of the 1-loop
mass matrix for the neutral Higgs bosons. We calculate the upper bound on the
lightest neutral Higgs boson mass under the assumption. It is found to be about
140 GeV for our choice of parameter values in the presence of the spontaneous
violation of the CP symmetry in the NMSSM. Thus, the possibility of the
spontaneous violation of the CP symmetry is not completely ruled out in the
Higgs sector of the NMSSM if the masses of the left-handed and the right-handed
scalar-top quarks are not degenerate. Further, the phenomenology of the
- mixing within the context of our model is studied. The lower
bound on CP violating phase in the - mixing is found to increase
if either decreases or increases.Comment: 21 pages, 5 figures, To appear in Phys. Rev.
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