Inflation with sterile scalar coupled to massive fermions and to gravity

In a recent paper by V. Barra et al. [3] it was shown that the consistency of the quantum theory of a sterile scalar coupled to massive fermions requires inclusion of odd-power terms in the potential of scalar self-interaction. One of the most important examples of a sterile scalar is the inflaton, which is typically a real scalar field that does not belong to representations of particle physics gauge groups, such as SU (2). Here we explore the effects of odd-power terms in the inflation potential on main observables, such as the scalar spectral index n(s) and the tensor-to-scalar ratio r, in the case of the inflaton's strong non-minimal coupling to gravity.