Large tensor-to-scalar ratio and running of the scalar spectral index   with Instep Inflation
  If a sizeable tensor-to-scalar ratio ~0.1 turns out to be detected and a negative running of the scalar spectral index ~0.01 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 non-renormalizable operators) can explain those features and produce enough inflation in the slow-roll regime. 
Guillermo Ballesteros and J. Alberto Casas
astro-ph.CO gr-qc hep-ph hep-th