Mutated hilltop inflation revisited

In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton–Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the $${\mathscr {W}}_{-1}$$ branch of the Lambert function. Depending on the model parameter mutated hilltop model renders two types of inflationary solutions: one corresponds to small inflaton excursion during observable inflation and the other describes large field inflation. The inflationary observables from curvature perturbation are in tune with the current data for a wide range of the model parameter. The small field branch predicts negligible amount of tensor to scalar ratio $$r\sim \mathscr {O}(10^{-4})$$, while the large field sector is capable of generating high amplitude for tensor perturbations, $$r\sim \mathscr {O}(10^{-1})$$. Also, the spectral index is almost independent of the model parameter along with a very small negative amount of scalar running. Finally we find that the mutated hilltop inflation closely resembles the $$\alpha $$-attractor class of inflationary models in the limit of $$\alpha \phi \gg 1$$