Cosmological Gravitational Wave Collider Physics
Abstract
Primordial tensor non-Gaussianity can probe massive particles present during inflation. We investigate this possibility in an effective field theory where the massless graviton mixes with the helicity-two mode of an additional massive spin-two field σij with cubic self-interactions. For constant sound speed, we compute the leading tensor power-spectrum correction and the tree-level bispectrum, finding novel analytical expressions for these quantities. In the mσ>3H/2 regime, we find a nonanalytic squeezed contribution that exhibits logarithmic oscillations with characteristic dependence (kL/kS)3/2± iμ, where μ=√(mσ2/H2−9/4). The oscillation frequency is set by the mass mσ, while the polarisation contractions determine the relative amplitudes of the different graviton helicity configurations. The same mixing generates corrections to the power spectrum and the bispectrum. We derive the associated quadrupolar modulation of short-scale tensor power spectrum and relate its amplitude to the model parameters. Finally, we explore how a slowly varying sound speed modifies the squeezed signal.~These results connect the two-point, three-point, and quadrupolar tensor signatures of massive spin-two fields in the cosmological gravitational wave collider.
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BibTeX
@misc{bhattacharya2026cosmological,
title = {{Cosmological Gravitational Wave Collider Physics}},
author = {Sukannya Bhattacharya and Matteo Fasiello and Anish Ghoshal and Gianmassimo Tasinato},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.29885},
eprint = {2610.29885},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.29885},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Cosmological Gravitational Wave Collider Physics
AU - Sukannya Bhattacharya
AU - Matteo Fasiello
AU - Anish Ghoshal
AU - Gianmassimo Tasinato
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.29885
UR - https://arxiv.org/abs/2610.29885
AB - Primordial tensor non-Gaussianity can probe massive particles present during inflation. We investigate this possibility in an effective field theory where the massless graviton mixes with the helicity-two mode of an additional massive spin-two field σ_ij with cubic self-interactions. For constant sound speed, we compute the leading tensor power-spectrum correction and the tree-level bispectrum, finding novel analytical expressions for these quantities. In the m_σ>3H/2 regime, we find a nonanalytic squeezed contribution that exhibits logarithmic oscillations with characteristic dependence (k_L/k_S)^3/2± iμ, where μ=√(m_σ^2/H^2−9/4). The oscillation frequency is set by the mass m_σ, while the polarisation contractions determine the relative amplitudes of the different graviton helicity configurations. The same mixing generates corrections to the power spectrum and the bispectrum. We derive the associated quadrupolar modulation of short-scale tensor power spectrum and relate its amplitude to the model parameters. Finally, we explore how a slowly varying sound speed modifies the squeezed signal.~These results connect the two-point, three-point, and quadrupolar tensor signatures of massive spin-two fields in the cosmological gravitational wave collider.
ER -