Gravitational wave background and non-Gaussianity as a probe of the curvaton scenario

We study observational implications of the stochastic gravitational wave background and a non-Gaussian feature of scalar perturbations on the curvaton mechanism of the generation of density/curvature fluctuations, and show that they can determine the properties of the curvature in a complementary manner to each other. Therefore even if Planck could not detect any non-Gaussianity, future space-based laser interferometers such as DE-CIGO or BBO could practically exhaust its parameter space.