6 research outputs found
Coleman-Weinberg Potential In Good Agreement With WMAP
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/dlnk is =~-10^-3. An SO(10) version naturally explains the
observed baryon asymmetry via non-thermal leptogenesis.Comment: v1: 6 pages, 1 table. v2: minor corrections. v3: 8 pages, added some
details, comments, references and 3 figures. v4: minor corrections, published
versio
Reheat temperature in supersymmetric hybrid inflation models
The allowed range of parameters for supersymmetric hybrid inflation and its
extensions are investigated. The lower bound on the reheat temperature T_r in
these models with hierarchical right handed neutrinos is found to be 3*10^7
GeV. (T_r as low as 100 GeV is possible for quasi degenerate right handed
neutrinos.) We also present revised estimates for the scalar spectral index and
the symmetry breaking scale associated with inflation.Comment: 15 pages, 8 figures, revtex4. v2: minor changes, matches published
versio
Supersymmetric And Smooth Hybrid Inflation In The Light Of WMAP3
In their minimal form both supersymmetric and smooth hybrid inflation yield a
scalar spectral index n_s close to 0.98, to be contrasted with the result
n_s=0.951+0.015-0.019 from WMAP3. To realize better agreement, following
hep-ph/0604198, we extend the parameter space of these models by employing a
non-minimal Kaehler potential. We also discuss non-thermal leptogenesis by
inflaton decay and obtain new bounds in these models on the reheat temperature
to explain the observed baryon asymmetry.Comment: 21 pages, 12 figures, revtex4. v2: minor revisions, additional
references, to appear in PR
Non-Canonical MSSM, Unification, And New Particles At The LHC
We consider non-canonical embeddings of the MSSM in high-dimensional orbifold
GUTs based on the gauge symmetry SU(N), N=5,6,7,8. The hypercharge
normalization factor k_Y can either have unique non-canonical values, such as
23/21 in a six-dimensional SU(7) model, or may lie in a (continuous) interval.
Gauge coupling unification and gauge-Yukawa unification can be realized in
these models by introducing new particles with masses in the TeV range which
may be found at the LHC. In one such example there exist color singlet
fractionally charged states.Comment: 1+25 pages, 5 figures. v2: Introduction revised, sections reordered,
figure 4 correcte
TeV scale leptogenesis with heavy neutrinos
Following a baryogenesis scenario proposed by Lazarides, Panagiotakopoulos
and Shafi, we show how the observed baryon asymmetry can be explained via
resonant leptogenesis in a class of supersymmetric models with an intermediate
mass scale M_I<~10^9 GeV. It involves the out of equilibrium decay of heavy
(<~M_I) right handed neutrinos at a temperature close to the TeV supersymmetry
breaking scale. Such models can also resolve the MSSM mu problem.Comment: 1+9 pages, no figure, comments added, minor revisions, to appear in
PR