An alternative framework for E-model inflation in supergravity

Abstract

AbstractWe 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 $$K_1$$ K 1 and $${\widetilde{K}}_1$$ K ~ 1 , which parameterize the same hyperbolic manifold with scalar curvature $${{{\mathcal {R}}}}_{K}=-2/N$$ R K = - 2 / N , where $$(-N)<0$$ ( - 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 $$K=K_1$$ K = K 1 , inflation can be attained for $$N=2$$ 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 $$K={\widetilde{K}}_1$$ K = K ~ 1 , which allows for quadratic- and quartic-like models with N values increasing with r and spectral index $$n_\mathrm{s}$$ n s close or even equal to its present central observational value.