Keeping the relation between the Starobinsky model and no-scale supergravity ACTive

We introduce a modification of the Starobinsky model in the form of an additional cubic Ricci scalar curvature term ∼ αR ³, scaled by a dimensionless parameter α, with the resulting inflaton potential being the standard Starobinsky potential modified to first parametric order by an additive term. The resulting potential is identical to the potential obtained by a modification of the superpotential employed in the construction of the Starobinsky model in the framework of no-scale supergravity, thus, extending the correspondence between a class of no-scale supergravity models and modifications of the Starobinsky model. We analyze the inflationary predictions of the model and find that for -4.2 × 10^-5 ≲ α ≲ -1.9 × 10^-5, the modified Starobinsky model is in full agreement with the recent observational data from the Atacama Cosmology Telescope, for a range of e-folds, N _★ = 50–60.