220 research outputs found
Light Dark Matter Candidate in B-L Gauged Radiative Inverse Seesaw
We study a radiative inverse seesaw model with local B-L symmetry, in which
we extend the neutrino mass structure that is generated through a kind of
inverse seesaw framework to the more generic one than our previous work. We
focus on a real part of bosonic particle as a dark matter and investigate the
features in O(1-80) GeV mass range, reported by the experiments such as CoGeNT
and XENON (2012).Comment: 10 pages, 1 table, 3 figures; version accepted for publication in
European Physical Journal
Two Component Dark Matters in S_4 x Z_2 Flavor Symmetric Extra U(1) Model
We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra
U(1) model with S_4 x Z_2 flavor symmetry. In our model, the lightest flavon
has very long lifetime of O(10^{18)) second which is longer than the age of the
universe, but not long enough to explain the PAMELA result ~ O(10^{26}) sec.
Such a situation could be avoidable by considering that the flavon is not the
dominant component of dark matters and the dominant one is the lightest
neutralino. With appropriate parameter set, density parameter of dark matter
and over-abundance of positron flux in cosmic-ray are realized at the same
time. There is interesting correlation between spectrum of positron flux and
V_{MNS}. No excess of anti-proton in cosmic-ray suggests that sfermions are
heavier than 4 TeV and the masses of the light Higgs bosons are degenerated.Comment: 22 pages, 4 figures, 2 tables; version accepted for publication in
Progress of Theoretical Physic
Fermionic Dark Matter in Radiative Inverse Seesaw Model with U(1)_{B-L}
We construct a radiative inverse seesaw model with local B-L symmetry, and
investigate the flavor structure of the lepton sector and the fermionic Dark
Matter. Neutrino masses are radiatively generated through a kind of inverse
seesaw framework. The PMNS matrix is derived from each mixing matrix of the
neutrino and charged lepton sector with large Dirac CP phase. We show that the
annihilation processes via the interactions with Higgses which are independent
on the lepton flavor violation, have to be dominant in order to satisfy the
observed relic abundance by WMAP. The new interactions with Higgses allow us to
be consistent with the direct detection result reported by XENON100, and it is
possible to verify the model by the exposure of XENON100 (2012).Comment: 15 pages, 1 table, 5 figures; version accepted for publication in
Physical Review
Two Loop Neutrino Model with Dark Matter and Leptogenesis
We study a two-loop induced radiative neutrino model at TeV scale with global
symmetry, in which we analyze dark matter and resonant leptogenesis. The
model includes two kinds of dark matter candidates. We discuss what kind of
dark matter can satisfy the observed relic density as well as the current
direct detection bound, and be simultaneously compatible with the leptogenesis.
We also discuss whether our resonant leptogenesis can be differentiated from
the other scenarios at TeV scale or not.Comment: 21 pages, 7 figures, version to appear in IJMP
Effect of Degenerate Particles on Internal Bremsstrahlung of Majorana Dark Matter
Gamma-rays induced by annihilation or decay of dark matter can be its smoking
gun signature. In particular, gamma-rays generated by internal bremsstrahlung
of Majorana and real scalar dark matter is promising since it can be a leading
emission of sharp gamma-rays. However in the case of Majorana dark matter, its
cross section for internal bremsstrahlung cannot be large enough to be observed
by future gamma-ray experiments if the observed relic density is assumed to be
thermally produced. In this paper, we introduce some degenerate particles with
Majorana dark matter, and show they lead enhancement of the cross section. As a
result, increase of about one order of magnitude for the cross section is
possible without conflict with the observed relic density, and it would be
tested by the future gamma-ray experiments such as GAMMA-400 and Cherenkov
Telescope Array (CTA). In addition, the constraints of perturbativity, positron
observation by the AMS experiment and direct search for dark matter are
discussed.Comment: 13 pages, 4 figures, version to appear in Physics Letters
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