Consistency relation for natural inflation with Planck 2015 data

Abstract

We consider the cosine Natural inflation model that is a good candidate to explain the initial accelerating phase of the universe. By computing the inflationary parameters in Einstein frame, we construct a consistency relation between the scalar spectral index, tensor-to-scalar ratio, as well as the running of the scalar spectral index and compare the results with recently released Planck 2015 observational data. Our results show that a Natural Inflation model in Einstein frame has a good agreement with the observational data.