Rescuing quadratic inflation

Inflationary models based on a single scalar field 5 with a quadratic potential V = 1/2m(2)phi(2) are disfavoured by the recent Planck constraints on the scalar index, n(s), and the tensor-to-scalar ratio for cosmological density perturbations, rT. In this paper we study how such a quadratic inflationary model can be rescued by postulating additional fields with quadratic potentials, such as might occur in sneutrino models, which might serve as either curvatons or supplementary inflatons. Introducing a second scalar field reduces but does not remove the pressure on quadratic inflation, but we find a sample of three-field models that are highly compatible with the Planck data on ns and rT. We exhibit a specific three-sneutrino example that is also compatible with the data on neutrino mass difference and mixing angles.