Inflation in $R^2$ supergravity with non-minimal superpotentials

Understand

We investigate the cosmological inflation in a class of supergravity models that are generalizations of non-supersymmetric $R^2$ models.

• Although such models have been extensively studied recently, especially after the launch of the PLANCK and BICEP2 data, the class of models that can be constructed has not been exhausted.
• In this note, working in a supergravity model that is a generalization of Cecotti's model, we show that the appearance of new superpotential terms, which are quadratic in the superfield $\, \Lambda$ that couples to the Ricci supermultiplet, alters substantially the form of the scalar potential.
• The arising potential has the form of the Starobinsky potential times a factor that is exponential in the inflaton field and dominates for large inflaton values.