613 research outputs found
Coannihilation Scenarios and Particle Spectroscopy in SU(4)_c x SU(2)_L x SU(2)_R
We identify a variety of coannihilation scenarios in a supersymmetric SU(4)_c
x SU(2)_L x SU(2)_R model with discrete left-right symmetry. Non-universal
gaugino masses, compatible with the gauge symmetry, play an essential role in
realizing gluino and bino-wino coannihilation regions that are consistent with
the WMAP dark matter constraints. We also explore regions of the parameter
space in which the little hierarchy problem is partially resolved. We present
several phenomenologically interesting benchmark points and the associated
sparticle and Higgs mass spectra.Comment: 16 pages, 5 figures and 1 tabl
From New to Large Field Inflation: Comparison with WMAP3
We briefly summarize and update a class of inflationary models from the early
eighties based on a quartic (Coleman-Weinberg) potential for a gauge singlet
scalar (inflaton) field. For vacuum energy scales comparable to the grand
unification scale, the scalar spectral index n_s=0.94-0.97, in very good
agreement with the WMAP three year results. The tensor to scalar ratio r<~0.14
while alpha=dn_s/d ln k=~-10^-3. For vacuum energy scales >~10^16 GeV, the
inflationary scenario switches from `new' to `large-field' (V\propto\phi^2)
inflation. An SO(10) version naturally explains the observed baryon asymmetry
via non-thermal leptogenesis.Comment: 7 pages, 4 figures, 1 table. Based on a talk given by Q. Shafi at the
2nd International Conference on The Dark Side of the Universe (DSU 2006),
Madrid (Spain), 20-24 June 200
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