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arXiv · 1806.00850

Probing the inflationary particle content: extra spin-2 field

Emanuela Dimastrogiovanni·Matteo Fasiello·Gianmassimo Tasinato
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Abstract

We study how inflationary observables associated with primordial tensor modes are affected by coupling the minimal field content with an extra spin-2 particle during inflation. We work with a model that is ghost-free at the fully non-linear level and show how the new degrees of freedom modify standard consistency relations for the tensor bispectrum. The extra interacting spin-2 field is necessarily massive and unitarity dictates its mass be in the $m \gtrsim H$ range. Despite the fact that this bound selects a decaying solution for the corresponding tensor mode, cosmological correlators still carry the imprints of such "fossil" fields. Remarkably, fossil(s) of spin $\geq 1$ generate distinctive anisotropies in observables such as the tensor power spectrum. We show how this plays out in our set-up.

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Emanuela Dimastrogiovanni, Matteo Fasiello, Gianmassimo Tasinato. 2018-06-03. Probing the inflationary particle content: extra spin-2 field. https://doi.org/10.1088/1475-7516%2F2018%2F08%2F016

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