Pure Natural Inflation Passes the ACT

TL;DR

Pure natural inflation, a single-field model, is compatible with recent CMB data from ACT and BAO, with certain parameter constraints under standard reheating assumptions.

Contribution

This paper demonstrates the compatibility of pure natural inflation with latest observational data and explores its parameter space under different reheating scenarios.

Findings

Model is compatible with ACT and BAO data.

Certain parameter space regions are favored under standard reheating.

Extension of the model also remains viable.

Abstract

Pure natural inflation is a compelling effectively single-field model of inflation stemming from a top-down approach to the acceleration mechanism. In this short letter we show that such model is compatible with the latest CMB constraints obtained from the Atacama Cosmology Telescope combined with baryon acoustic oscillation data from the Dark Energy Spectroscopic Instrument. Under both the instantaneous reheating hypothesis and standard assumptions for reheating, we rule in a non-trivial fraction of the parameter space. We apply our analysis also to a phenomenological extension of the model and chart its viable parameter space.