1,035 research outputs found
D-term inflation and neutrino mass
We study a -term inflation scenario in a model extended from the minimal
supersymmetric standard model (MSSM) by two additional abelian factor groups
focussing on its particle physics aspects. Condensates of the fields related to
the inflation can naturally give a possible solution to both the -problem
in the MSSM and the neutrino mass through their nonrenormalizable couplings to
the MSSM fields. Mixings between neutrinos and neutralinos are also induced by
some of these condensates. Small neutrino masses are generated by a weak scale
seesaw mechanism as a result of these mixings. Moreover, the decay of the
condensates may be able to cause the leptogenesis. Usually known discrepancy
between both values of a Fayet-Iliopoulos -term which are predicted by the
COBE normalization and also by an anomalous U(1) in the weakly-coupled
superstring might be reconciled.Comment: 21 pages, LaTeX, small modifications, one reference adde
Reconciliation of CDM abundance and in a radiative seesaw model
We reexamine relic abundance of a singlet fermion as a CDM candidate, which
contributes to the neutrino mass generation through radiative seesaw mechanism.
We search solutions for Yukawa couplings and the mass spectrum of relevant
fields to explain neutrino oscillation data. For such solutions, we show that
an abundance of a lightest singlet fermion can be consistent with WMAP data
without conflicting with both bounds of and . This reconciliation does not need any modification of the original
radiative seesaw model other than by specifying flavor structure of Yukawa
couplings and taking account of coannihilation effects.Comment: 16 pages, 2 figures, accepted version for publication
Gaugino CP phases and EDMs in the extended gauge mediation SUSY breaking
We study phenomenological aspects of the soft supersymmetry breaking
parameters in a model with the extended gauge mediation supersymmetry breaking.
In this model gaugino masses can be non-universal and as its result physical
CP-phases remain in the gaugino sector even after the R-transformation. These
phases contribute to the electric dipole moment (EDM) of an electron and a
neutron. We show that their experimental bounds can be satisfied even for the
situation such that there exist the order one CP-phases and the masses of
superpartners are of the order of 100 GeV.Comment: LaTeX, 26 pages, 6 figure
-term as the origin of baryon and lepton number asymmetry
We study a possibility of combining an origin of the -term and the
baryon and lepton number asymmetry. If we assume that the -term is
generated through a flat direction of a singlet scalar field, the coherent
oscillation of this condensate around its potential minimum can store the
global U(1) charge asymmetry. The decay of this condensate can distribute this
asymmetry into the lepton and baryon number asymmetry as far as its decay
occurs at an appropriate temperature. We examine the compatibility between this
scenario and the small neutrino mass generation based on both the ordinary
seesaw mechanism and the bilinear R-parity violating terms.Comment: 22 pages, published versio
Effect on the electron EDM due to abelian gauginos in SUSY extra U(1) models
The electric dipole moment of an electron (EDME) is investigated in the
supersymmetric extra U(1) models. Neutralino sector is generally extended in
these models and then the neutralino contribution will be important for the
analysis of the EDME. Kinetic term mixings of abelian gauginos are taken into
account in our analysis. Numerical results for the extra U(1) models show that
the EDME can be affected by the extra U(1) in a certain range of soft
supersymmetry breaking parameters even if the extra U(1) gauge boson is heavy.
The EDME may be a clue to find an extended gauge structure in the
supersymmetric models.Comment: 16 pages, latex, 3 figure
Mass bound of the lightest neutral Higgs scalar in the extra U(1) models
The upper mass bound of the lightest neutral Higgs scalar is studied in the
problem solvable extra U(1) models by using the analysis of the
renormalization group equations. In order to restrict the parameter space we
take account of a condition of the radiative symmetry breaking and some
phenomenological constraints. We compare the bound obtained based on this
restricted parameter space with the one of the next to the minimal
supersymmetric standard model (NMSSM). Features of the scalar potential and
renormalization group equations of the Yukawa couplings among Higgs chiral
supermultiplets are rather different between them. They can reflect in this
bound.Comment: 22 pages, latex, 11 eps-figure
The Invisible Axion and Neutrino Masses
We show that in any invisible axion model due to the effects of effective
non-renormalizable interactions related to an energy scale near the
Peccei-Quinn, grand unification or even the Planck scale, active neutrinos
necessarily acquire masses in the sub-eV range. Moreover, if sterile neutrinos
are also included and if appropriate cyclic symmetries are imposed, it is
possible that some of these neutrinos are heavy while others are light.Comment: An example included and new references added. To appear in PR
Leptogenesis and dark matter unified in a non-SUSY model for neutrino masses
We propose a unified explanation for the origin of dark matter and baryon
number asymmetry on the basis of a non-supersymmetric model for neutrino
masses. Neutrino masses are generated in two distinct ways, that is, a
tree-level seesaw mechanism with a single right-handed neutrino, and one-loop
radiative effects by a new additional doublet scalar. A spontaneously broken
U(1) brings a symmetry which restricts couplings of this new
scalar and controls the neutrino masses. It also guarantees the stability of a
CDM candidate. We examine two possible candidate for the CDM. We also show that
the decay of a heavy right-handed neutrino related to the seesaw mechanism can
generate baryon number asymmetry through leptogenesis.Comment: 21 pages, 3 figures, extended version for publication, references
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