2,920 research outputs found
Flat direction condensate instabilities in the MSSM
Coherently oscillating scalar condensates formed along flat directions of the
MSSM scalar potential are unstable with respect to spatial perturbations if the
potential is flatter than phi^2, resulting in the formation of non-topological
solitons such as Q-balls. Using renormalization group we calculate the
corrections to the phi^2 potential for a range of flat directions and show that
unstable condensates are a generic feature of the MSSM. Exceptions arise for an
experimentally testable range of stop and gluino masses when there are large
admixtures of stops in the flat direction scalar.Comment: 9 pages, 9 encapsulated postscript figure
Inflation in large N limit of supersymmetric gauge theories
Within supersymmetry we provide an example where the inflaton sector is
derived from a gauge invariant polynomial of SU(N) or SO(N) gauge theory.
Inflation in our model is driven by multi-flat directions, which assist
accelerated expansion. We show that multi-flat directions can flatten the
individual non-renormalizable potentials such that inflation can occur at
sub-Planckian scales. We calculate the density perturbations and the spectral
index, we find that the spectral index is closer to scale invariance for large
N. In order to realize a successful cosmology we require large N of order,
N~600.Comment: 10 pages, LaTeX2e, misprints corrected, version accepted for
publishin
Recent progress in Affleck-Dine baryogenesis
In the MSSM, cosmological scalar field condensates formed along flat
directions of the scalar potential (Affleck-Dine condensates) are typically
unstable with respect to formation of Q-balls, a type of non-topological
soliton. I discuss the creation and growth of the quantum seed fluctuations
which catalyse the collapse of the condensate. In D-term inflation models, the
fluctuations of squark fields in the flat directions also give rise to
isocurvature density fluctuations stored in the Affleck-Dine condensate. After
the condensate breaks up, these can be perturbations in the baryon number, or,
in the case where the present neutralino density comes directly from B-ball
decay, perturbations in the number of dark matter neutralinos. The latter case
results in a large enhancement of the isocurvature perturbation, which should
be observable by PLANCK.Comment: 8 pages, 2 figures; invited talk at COSMO9
Simulations of Q-Ball Formation
The fragmentation of the Affleck-Dine condensate is studied by utilizing 3+1
dimensional numerical simulations. The 3+1 dimensional simulations confirm that
the fragmentation process is very similar to the results obtained by 2+1
dimensional simulations. We find, however, that the average size of Q-balls in
3+1 dimensions is somewhat larger that in 2+1 dimensions. A filament type
structure in the charge density is observed during the fragmentation process.
The resulting final Q-ball distribution is strongly dependent on the initial
conditions of the condensate and approaches a thermal one as the energy-charge
ratio of the Affleck-Dine condensate increases.Comment: 9 pages, 8 figures; corrected typos (v2,v3
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