If a sizeable tensor-to-scalar ratio $\sim 0.1$ turns out to be detected and a negative running of the scalar spectral index $\sim {10}^{-2}$ is significantly required by the data, the vast majority of single field models of inflation will be ruled out. We show that a flat tree-level effective potential, lifted by radiative corrections and by the imprints of a high energy scale (in the form of nonrenormalizable operators) can explain those features and produce enough inflation in the slow-roll regime.

• Received 6 October 2014

DOI:https://doi.org/10.1103/PhysRevD.91.043502