Sneutrino Inflation in the Light of WMAP: Reheating, Leptogenesis and Flavour-Violating Lepton Decays

We reconsider the possibility that inflation was driven by a sneutrino - the scalar supersymmetric partner of a heavy singlet neutrino - in the minimal seesaw model of neutrino masses. We show that this model is consistent with data on the cosmic microwave background (CMB), including those from the WMAP satellite. We derive and implement the CMB constraints on sneutrino properties, calculate reheating and the cosmological baryon asymmetry arising via leptogenesis from neutrino and sneutrino decays following sneutrino inflation. This is achieved by solving a coupled set of Boltzmann equations describing inflaton decay and leptogenesis in this scenario, and by relating them to light neutrino masses. We show that this scenario is compatible with a low reheating temperature that avoids the gravitino problem, and calculate its predictions for flavour-violating decays of charged leptons. We find that mu -> e gamma should occur close to the present experimental upper limits, as might also tau -> mu gamma.