84 research outputs found
Hillclimbing inflation
We propose a new class of inflationary models in which inflation takes place
while the inflaton is climbing up a potential hill due to a coupling to
gravity. We study their attractor behavior, and investigate its relation with
known attractors. We also discuss a possible realization of this type of models
with the natural inflation, and show that the inflationary predictions come
well within the region consistent with the observation of the cosmic microwave
background.Comment: 5 pages, 3 figure
Sterile neutrino dark matter from right-handed neutrino oscillations
We study a scenario where sterile neutrino (either warm or cold) dark matter
(DM) is produced through (nonresonant) oscillations among right-handed
neutrinos (RHNs) and can constitute the whole DM in the Universe, in contrast
to the conventional sterile neutrino production through its mixing with the
left-handed neutrinos. The lightest RHN can be sterile neutrino DM whose mixing
with left-handed neutrinos is sufficiently small while heavier RHNs can have
non-negligible mixings with left-handed neutrinos to explain the neutrino
masses by the seesaw mechanism. We also demonstrate that, in our scenario, the
production of sterile RHN DM from the decay of a heavier RHN is subdominant
compared with the RHN oscillation production due to the X-ray and small-scale
structure constraints.Comment: Version to appear in PR
Next to new minimal standard model
We suggest a minimal extension of the standard model, which can explain
current experimental data of the dark matter, small neutrino masses and baryon
asymmetry of the universe, inflation, and dark energy, and achieve gauge
coupling unification. The gauge coupling unification can explain the charge
quantization, and be realized by introducing six new fields. We investigate the
vacuum stability, coupling perturbativity, and correct dark matter abundance in
this model by use of current experimental data.Comment: 17 pages, 8 figure
Planck scale boundary conditions in the standard model with singlet scalar dark matter
We investigate Planck scale boundary conditions on the Higgs sector of the
standard model with a gauge singlet scalar dark matter. We will find that
vanishing self-coupling and Veltman condition at the Planck scale are realized
with the 126 GeV Higgs mass and top pole mass, 172 GeV
173.5 GeV, where a correct abundance of scalar dark matter is obtained with
mass of 300 GeV 1 TeV. It means that the Higgs
potential is flat at the Planck scale, and this situation can not be realized
in the standard model with the top pole mass.Comment: 12 pages, 4 figures, version accepted for publication in JHE
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