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arXiv · 2408.07069

Cosmological collider non-Gaussianity from multiple scalars and $R^2$ gravity

Shuntaro Aoki·Anish Ghoshal·Alessandro Strumia
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Abstract

Cosmological collider signals of primordial non-Gaussianity arise at tree level when an extra scalar has Hubble mass during inflation. We critically review the formalism finding that a large class of inflationary theories, based on Planck-scale physics, predict a scalar bi-spectrum around the gravitational floor level. This mild signal arises for example in $R^2$ gravity, in the regime where its gravitational scalar has Hubble-scale mass. Signals much above the gravitational floor arise in theories where scalars undergo multiple turns during inflation, thanks to sub-Planckian physics.

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Shuntaro Aoki, Anish Ghoshal, Alessandro Strumia. 2024-08-13. Cosmological collider non-Gaussianity from multiple scalars and $R^2$ gravity. https://arxiv.org/abs/2408.07069

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