Impact of Heavy Modes on Primordial Black Hole Formation
Abstract
Primordial black holes (PBHs) form from rare fluctuations in the high-density tail of the primordial distribution, making their abundance highly sensitive to primordial non-Gaussianity. Heavy fields during inflation can source such non-Gaussianity, producing characteristic signatures widely explored in cosmological collider physics, yet its impact on PBH formation remains largely unexamined. We investigate this question within quasi-single-field inflation (QSFI), the minimal realization that couples a heavy field to the inflaton. Unlike most PBH studies that consider only the bispectrum, the QSFI can generate a sizable trispectrum alongside the bispectrum, allowing us to investigate their combined effects on PBH formation. In our leading-order calculation, heavy-field non-Gaussianities can amplify the high-density tail and substantially enhance PBH production. Within the parameter scan, the largest enhancement occurs at the smallest heavy-field mass and the largest sound-speed ratio considered. The trispectrum contribution can be comparable to that of the bispectrum and may even dominate the total non-Gaussian correction. Our results establish PBH abundance as a novel observational channel for cosmological collider physics, demonstrating how heavy fields during inflation can significantly shape PBH formation.
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BibTeX
@misc{li2026impact,
title = {{Impact of Heavy Modes on Primordial Black Hole Formation}},
author = {Guo-He Li and Mian Zhu and Chunshan Lin},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29743},
eprint = {2609.29743},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29743},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Impact of Heavy Modes on Primordial Black Hole Formation
AU - Guo-He Li
AU - Mian Zhu
AU - Chunshan Lin
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29743
UR - https://arxiv.org/abs/2609.29743
AB - Primordial black holes (PBHs) form from rare fluctuations in the high-density tail of the primordial distribution, making their abundance highly sensitive to primordial non-Gaussianity. Heavy fields during inflation can source such non-Gaussianity, producing characteristic signatures widely explored in cosmological collider physics, yet its impact on PBH formation remains largely unexamined. We investigate this question within quasi-single-field inflation (QSFI), the minimal realization that couples a heavy field to the inflaton. Unlike most PBH studies that consider only the bispectrum, the QSFI can generate a sizable trispectrum alongside the bispectrum, allowing us to investigate their combined effects on PBH formation. In our leading-order calculation, heavy-field non-Gaussianities can amplify the high-density tail and substantially enhance PBH production. Within the parameter scan, the largest enhancement occurs at the smallest heavy-field mass and the largest sound-speed ratio considered. The trispectrum contribution can be comparable to that of the bispectrum and may even dominate the total non-Gaussian correction. Our results establish PBH abundance as a novel observational channel for cosmological collider physics, demonstrating how heavy fields during inflation can significantly shape PBH formation.
ER -