6,372 research outputs found
The Fate of SUSY Flat Directions and their Role in Reheating
We consider the role of supersymmetric flat directions in reheating the
Universe after inflation. One or more flat directions can develop large vevs
during inflation, which can potentially affect reheating by slowing down
scattering processes among inflaton decay products or by coming to dominate the
energy density of the Universe. Both effects occur only if flat directions are
sufficiently long-lived. The computation of their perturbative decay rate, and
a simple estimate of their nonperturbative decay have led to the conclusion
that this is indeed the case. In contrast, we show that flat directions can
decay quickly through nonperturbative channels in realistic models. The mass
matrix for MSSM excitations around flat directions has nondiagonal entries,
which vary with the phase of the (complex) flat directions. The quasi-periodic
motion of the flat directions results in a strong parametric resonance, leading
to the rapid depletion of the flat direction within its first few rotations.
This may preclude any significant role for the flat directions in reheating the
Universe after inflation in models in which the inflaton decays perturbatively.Comment: 30 pages, 6 .ps figures. Final published versio
Dark Energy and Dark Matter
A brief overview of our current understanding of abundance and properties of
dark energy and dark matter is presented. A more focused discussion of
supersymmetric dark matter follows. Included is a frequentist approach to the
supersymmetric parameter space and consequences for the direct detection of
dark matter.Comment: 12 pages, 8 figures, Summary of talk given at the XXIV International
Symposium on Lepton Photon Interactions at High Energies, Hamburg Germany,
August 200
The violent Universe: the Big Bang
Four lectures on Big Bang cosmology, including microwave background
radiation, Big Bang nucleosynthesis, dark matter, inflation, and baryogenesis.Comment: 47 pages, 19 figures, Set of four lectures given at the 2009 European
School of High-Energy Physics, Bautzen, Germany, June 200
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