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arXiv · 2412.01734

Constraints on the Pre-Big Bang scenario from a cosmological interpretation of the NANOGrav data

P. Conzinu·G. Fanizza·M. Gasperini·E. Pavone·L. Tedesco·G. Veneziano
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Abstract

We discuss a recently proposed fit of the 15-year data set obtained from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) in terms of a relic stochastic background of primordial gravitons, produced in the context of the string cosmology pre-big bang scenario. We show that such interpretation cannot be reconciled with a phenomenologically viable minimal version of such scenario, while it can be allowed if one considers an equally viable but generalised, non-minimal version of pre-big bang evolution. Maintaining the $S$-duality symmetry throughout the high-curvature string phase is possible although somewhat disfavoured. The implications of this non-minimal scenario for the power spectrum of curvature perturbations are also briefly discussed.

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P. Conzinu, G. Fanizza, M. Gasperini, E. Pavone, L. Tedesco, G. Veneziano. 2024-12-02. Constraints on the Pre-Big Bang scenario from a cosmological interpretation of the NANOGrav data. https://doi.org/10.1088/1475-7516%2F2025%2F02%2F039

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