Revisiting the Minimal Chaotic Inflation Model

We point out that the prediction of the minimal chaotic inflation model is altered if a scalar field takes a large field value close to the Planck scale during inflation due to a negative Hubble induced mass. In particular, we show that the inflaton potential is effectively suppressed at a large inflaton field value in the presence of such a scalar field. The scalar field may be identified with the standard model Higgs field or flat directions in supersymmetric theory. With such spontaneous suppression, we find that the minimal chaotic inflation model, especially the model with a quadratic potential, is consistent with recent observations of the cosmic microwave background fluctuation without modifying the inflation model itself.