2018/06/03 by Emanuela Dimastrogiovanni, Matteo Fasiello, Gianmassimo Tasinato · 1 citation
Physics and Astronomy · #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2018/08/016
25 pages, 3 figures
arxiv created 2018/06/03 · arxiv updated 2018/08/22
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 ≥ 1 generate distinctive anisotropies in observables such as the tensor power spectrum. We show how this plays out in our set-up.