Probing the Perturbative Reheating History of Decaying Oscillatory Inflation with ACT Constraints
arXiv:2508.16538 · doi:10.1016/j.dark.2026.102247
Abstract
Precision measurements of the Cosmic Microwave Background (CMB) now offer a powerful probe of the unknown reheating epoch. In this work, we scrutinize a decaying oscillatory inflation model inspired by supergravity, replacing standard ad hoc reheating assumptions with a fully dynamical calculation based on perturbative inflaton decay. By numerically tracking the energy transfer and the evolution of the equation of state, we eliminate the theoretical degeneracy associated with the reheating duration, directly linking the microphysical decay rate to the observable spectral index . We confront these self-consistent predictions with the combined constraints from Planck 2018 and ACT DR6. Our analysis demonstrates that the viable parameter space is tightly bracketed: the thermalization requirement from Big Bang Nucleosynthesis imposes a strict lower bound on the coupling strength, while the latest ACT data strongly favor scenarios with efficient reheating ( GeV), effectively pushing the model towards the instantaneous reheating limit. This study highlights the capability of modern CMB data to constrain the particle physics nature of the early universe.
15 pages, 3 figures; journal reference and DOI added
References in corpus (19)
- DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
- Reheating constraints to inflationary models
- DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars
- Reheating predictions in single field inflation
- Probing reheating with primordial spectrum
- Curing inflationary degeneracies using reheating predictions and relic gravitational waves
- Reheating ACTs on Starobinsky and Higgs inflation
- Kinetically Modified Palatini Inflation Meets ACT Data
- Constraining the general reheating phase in the -attractor inflationary cosmology
- Enhanced Curvature Perturbation and Primordial Black Hole Formation in Two-stage Inflation with a break
- Primordial black holes and induced gravitational waves from double-pole inflation
- Model independent bounds for the number of -folds during the evolution of the universe
- Sudden braking and turning with a two-field potential bump: primordial black hole formation
- Probing the reheating phase through primordial magnetic field and CMB
- Growth of power spectrum due to decrease of sound speed during inflation
- Resonant amplification of curvature perturbations in inflation model with periodical derivative coupling
- Primordial non-Guassianity in inflation with gravitationally enhanced friction
- Constraining inflation with nonminimal derivative coupling with the Parkes Pulsar Timing Array third data release
- Frame-Dependence of the Hamilton-Jacobi Formalism for Inflation and Reheating in Non-Minimal Gravity