515 research outputs found
PAMELA and ATIC Anomalies in Decaying Gravitino Dark Matter Scenario
Motivated by the recent results from the PAMELA and ATIC, we study the
cosmic-ray electron and positron produced by the decay of gravitino dark
matter. We calculate the cosmic-ray electron and positron fluxes and discuss
implications to the PAMELA and ATIC data. In this paper, we will show that the
observed anomalous fluxes by the PAMELA and ATIC can be explained in such a
scenario. We will also discuss the synchrotron radiation flux from the Galactic
center in such a scenario.Comment: Prepared for the proceedings of Dark 2009:Seventh International
Heidelberg Conference on Dark Matter in Astro and Particle Physic
Indirect Probe of Electroweak-Interacting Particles with Mono-Lepton Signatures at Hadron Colliders
Electroweak-interacting massive particles (EWIMPs) exist in a broad class of
new physics models beyond the Standard Model. Searching for such particles is
one of most primary goal at the LHC and future colliders. The EWIMP generally
affects the LHC signatures through quantum corrections even without direct
productions. By measuring the Standard Model processes precisely, we can
indirectly probe the EWIMPs. In this paper, we study the current constraint and
future prospect of the EWIMPs by using the precision measurements of
mono-lepton production from the charged Drell-Yan processes at hadron
colliders. We found the mono-lepton signature can be a better probe than
dilepton signature from the neutral Drell-Yan processes.Comment: 10 pages, 7 figure
Relic abundance of dark matter in the minimal universal extra dimension model
We investigate the relic abundance of dark matter in the minimal universal
extra dimension model including resonance processes by second Kaluza-Klein (KK)
particles in all coannihilation processes. After including second KK resonance
processes, the relic abundance of dark matter is reduced by about 30%. Thus,
the compactification scale 1/R of the extra dimension consistent with the WMAP
observation is increased by a few hundred GeV. As a result, the cosmologically
allowed compactification scale is 600 GeV < 1/R < 1400 GeV for Lambda R = 20.Comment: 24 pages, 7 figure
Sneutrino Inflation with Asymmetric Dark Matter
The asymmetric dark matter scenario is known to give an interesting solution
for the cosmic coincidence problem between baryon and dark matter densities. In
the scenario, the dark matter asymmetry, which is translated to the dark matter
density in the present universe, is transferred from the B-L asymmetry
generated in the early universe. On the other hand, the generation of the B-L
asymmetry is simply assumed, though many mechanisms for the generation are
expected to be consistent with the scenario. We show that the generation of the
asymmetry in the sneutrino inflation scenario works similarly to the asymmetric
dark matter scenario, because the non-renormalizable operator which translates
the B-L asymmetry to the dark matter asymmetry is naturally obtained by
integrating right-handed neutrinos out. As a result, important issues
concerning cosmology (inflation, the mass density of dark matter, and the
baryon asymmetry of the universe) as well as neutrino masses and mixing have a
unified origin, namely, the right-handed neutrinos.Comment: 11 pages, 4 figures; v2: reference added, Fig. 3 changed and
explanation added; v3: version accepted for publication in PR
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