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arXiv · 2507.12868

The Preheating Stage on The Starobinsky Inflation after ACT

Norma Sidik Risdianto·Romy Hanang Setya Budhi·Nehla Shobcha·Apriadi Salim Adam·Muhammad Abdan Syakura
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Abstract

Recent ACT results favor larger e-fold numbers, which tighten the reheating requirements in Starobinsky inflation. We show that efficient reheating generically requires an additional spectator-assisted preheating stage. The preheating dynamics and reheating temperature must be significantly modified to accommodate the higher reheating temperature. We present viable parameter sets compatible with PBH formation and the preferred reheating mechanism in this model. Furthermore, the momentum spectrum evolves from infrared-dominated modes at the early stage of preheating to higher-momentum modes at later times, supporting our scenario.

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Norma Sidik Risdianto, Romy Hanang Setya Budhi, Nehla Shobcha, Apriadi Salim Adam, Muhammad Abdan Syakura. 2026-09-12. The Preheating Stage on The Starobinsky Inflation after ACT. https://doi.org/10.1088/1402-4896%2Faea064

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