An alternative framework for E-model inflation in supergravity

Abstract

We present novel realizations of E-model inflation within Supergravity which are largely associated with the existence of a pole of order one in the kinetic term of the (gauge-singlet) inflaton superfield. This pole arises due to the selected logarithmic Kähler potentials K_1 and {widetilde{K}}_1, which parameterize the same hyperbolic manifold with scalar curvature {{{mathcal {R}}}}_{K}=-2/N, where (-N)<0 is the coefficient of a logarithmic term. The associated superpotential W exhibits the same R charge with the inflaton-accompanying superfield and includes all the allowed renormalizable terms. For K=K_1, inflation can be attained for N=2 at the cost of some tuning regarding the coefficients of the W terms and predicts a tensor-to-scalar ratio r at the level of 0.001. The tuning can be totally eluded for K={widetilde{K}}_1, which allows for quadratic- and quartic-like models with N values increasing with r and spectral index n_mathrm{s} close or even equal to its present central observational value.