Gauss–Bonnet inflation: perturbations, reheating and observational constraints

We present a comprehensive analysis of slow-roll inflation incorporating Gauss-Bonnet corrections within modified gravity frameworks. The model features a non-minimal coupling between the inflaton field and the Gauss-Bonnet invariant, with the coupling function [Formula: see text]([Formula: see text]) inversely proportional to the scalar potential [Formula: see text]([Formula: see text]). We derive the complete set of background equations, slowroll parameters, and cosmological perturbations within this framework. The scalar spectral index [Formula: see text] and tensor-to-scalar ratio [Formula: see text] are computed for a class of exponential-potential models, showing excellent agreement with Planck 2018 and ACT 2024 observational constraints. Furthermore, we extend the analysis to include reheating dynamics, primordial non-Gaussianity, and comparison with latest CMB data.