Primordial perturbations in Type III hilltop inflation models

TL;DR

This paper analytically calculates the primordial curvature perturbation spectrum in Type III hilltop inflation, constrains model parameters with CMB data, and finds quantum loop corrections are negligible, supporting the model's validity.

Contribution

It provides an analytical computation of the power spectrum in Type III hilltop inflation and assesses quantum corrections, which were previously not thoroughly analyzed.

Findings

Primordial black holes can form from small-scale perturbations.

Quantum loop corrections are negligible for 60 e-folds of inflation.

Model parameters are consistent with current CMB data.

Abstract

We analytically compute the power spectrum of primordial curvature perturbations in Type III hilltop inflation models under the slow-roll approximation. The model parameters are constrained using current Cosmic Microwave Background (CMB) data. The curvature perturbations that exit the horizon at small scales show sufficiently large amplitudes to produce primordial black holes (PBHs). We then consider the quantum one-loop corrections in these models from both the self-interaction of the inflaton and its interaction with the waterfall field. We show the loop corrections in both cases for 60 e-folds of inflation are negligible, ensuring the tree-level results are reliable within the chosen parameter regime.