Topics in supersymmetric astro-particle physics

Supersymmetry plays an important role in particle physics model building. Besides its power to solve the hierarchy problem, it opens up new possibilities to solve some of the outstanding issues in cosmology like inflation, baryogenesis, and dark matter. Consequently, most current attempts to derive realistic particle models which can address cosmological questions are being made in the context of supersymmetry. Four case studies are presented which examine issues in dark matter, inflation, and baryogenesis with a special emphasis on supersymmetry. The issues considered are stability of supersymmetric dark matter in the presence of R-parity violation in the heavy right-handed neutrino sector, the effect of final state self-interactions on parametric resonance decay of the inflaton, parametric resonance for complex fields, where the last two studies are motivated by supersymmetry, and the effect of reheating on baryogenesis from supersymmetric flat directions. The conclusions resulting from these studies range from a dependence of the dark matter decay rate on the nature of R-parity violating terms to (in principle) important modifications of simple parametric resonance in the case of supersymmetry and to substantial change in the estimates for the baryon asymmetry of the universe for a large subset of supersymmetric flat directions when only the standard model gauge symmetry is imposed.