101 research outputs found
SUSY CP Problem in Gauge Mediation Model
SUSY CP problem in the gauge mediation supersymmetry breaking model is
reconsidered. We pay particular attention to two sources of CP violating phases
whose effects were not seriously studied before; one is the effect of the
breaking of the GUT relation among the gaugino masses due to the field
esponsible for the GUT symmetry breaking, and the other is the supergravity
effect on the supersymmetry breaking parameters, in particular, on the
bi-linear supersymmetry breaking Higgs mass term. We show that both of them can
induce too large electric dipole moments of electron, neutron, and so on, to be
consistent with the experimental bounds.Comment: 15 pages, 3 figures, corrected typos, The version to appear in PL
Light Higgsino and Gluino in -invariant Direct Gauge Mediation
We provide a simple solution to the - problem in the
"-invariant direct gauge mediation model". With the solution, the Higgsino
and gluino are predicted to be light as GeV and
TeV, respectively. Those gluino and Higgsino can be accessible
at the LHC and future collider experiments. Moreover, dangerous dimension five
operators inducing rapid proton decays are naturally suppressed by the
-symmetry.Comment: 14 pages, 3 figure
Upper Bounds on Gluino, Squark and Higgisino Masses in the Focus Point Gaugino Mediation with a Mild Fine Tuning
We show that upper bounds on the masses for gluino, squarks and higgsino are
TeV, TeV and
GeV in a focus point gaugino mediation. Here, we impose a mild fine tuning
. This result shows that it is very challenging for the LHC to
exclude the focus point gaugino mediation with the mild fine tuning. However,
the ILC may have a potential for excluding the focus point gaugino mediation
with such a mild fine tuning. It is also shown that vector-like matters reduce
the required masses of the squark (stop) and gluino to explain the observed
Higgs boson mass and enhance the testability of the model at the LHC. The
fine-tuning is still kept mild.Comment: 13 pages, 2 figure
Focus Point in Gaugino Mediation ~ Reconsideration of the Fine-tuning Problem ~
We reconsider the fine-tuning problem in SUSY models, motivated by the recent
observation of the relatively heavy Higgs boson and non-observation of the SUSY
particles at the LHC. Based on this thought, we demonstrate a focus point-like
behavior in a gaugino mediation model, and show that the fine-tuning is indeed
reduced to about 2 percent level if the ratio of the gluino mass to wino mass
is about 0.4 at the GUT scale. We show that such a mass ratio may arise
naturally in a product group unification model without the doublet-triplet
splitting problem. This fact suggests that the fine-tuning problem crucially
depends on the physics at the high energy scale.Comment: 13 pages, 4 figures; published versio
Effects of Large Threshold Corrections in Supersymmetric Type-I Seesaw Model
We investigate lepton flavor violating (LFV) radiative processes and the
relic abundance of neutralino dark matter in supersymmetric type-I seesaw
model. We carefully derive threshold corrections to the flavor off-diagonal
elements of slepton mass matrix and up-type Higgs mass squared and find that
they can be large in the case of large . We examine how the branching
ratios of LFV radiative decays and the relic abundance of neutralino dark
matter can be significantly affected by the large threshold corrections. Soft
scalar mass squared parameter of up-type Higgs scalar is also affected by the
threshold corrections. Since the higgsino mass depends on the mass parameter
for up-type Higgs, the LFV processes and the relic abundance of the neutralino
dark matter are correlated with each other. We show that there are parameter
regions where the predictions of the relic abundance of neutralino dark matter
are consistent with WMAP observation and the branching ratios of LFV radiative
decays are predicted to be testable in future experiments. We find that the
masses of scalar supersymmetric particles are not necessarily small so that the
branching ratios of LFV decays can be testable in future experiment, which is
distinctive feature of this scenario.Comment: 32 pages, 6 figures, references are added, the version to appear in
JHE
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