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  • Open Access

Inflationary constraints on the moduli-dependent species scale in modular invariant theories

Shuntaro Aoki1,* and Hajime Otsuka2,†

  • *Contact author: shuntaro1230@gmail.com
  • †Contact author: otsuka.hajime@phys.kyushu-u.ac.jp
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Phys. Rev. D 112, 046006 – Published 6 August, 2025

DOI: https://doi.org/10.1103/k3xy-5r32

Abstract

We demonstrate that a broad class of modular inflation models predicts the emergence of new physics within an energy range of approximately 1015 to 1017  GeV. This prediction arises by comparing the moduli-dependent species scale with observational constraints on inflation. Specifically, we illustrate this within the context of SL(2,Z)-modular inflation models by reexpressing inflationary observables in terms of the species scale. We further discuss the implications of this approach for generic Calabi-Yau threefolds.

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Phys. Rev. D 112, 046006– Published 6 August, 2025
  • Received 20 November 2024
  • Accepted 21 July 2025
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