We revisit higher order corrections to the Starobinsky inflationary model using the most recent P-ACT-LB-BK18 data, which exhibits a mild but definite tension with the predictions of the original model. Our results demonstrate how even small higher order deformations of the Ricci scalar (e.g. R 3 , R 4 , ⋅⋅⋅) can bring the model into better agreement with current data and impose nontrivial constraints on the post-inflationary dynamics.
Park et al. (Wed,) studied this question.