Probing dark matter isocurvature with primordial non-Gaussianity

Michael Geller, Soubhik Kumar, Lian Tao Wang

Research output: Contribution to journalArticlepeer-review

Abstract

Multiple fields can become dynamical during the inflationary epoch. We consider an example where a light field acquires isocurvature fluctuations during inflation and contributes to the dark matter abundance at late times. Interactions between the light field and the adiabatic sector contribute to mixed adiabatic-isocurvature non-Gaussianity (NG). We show the resulting form of NG has a different kinematic dependence than the `local shape' commonly considered, and highlight the parameter space where a dedicated search is expected to significantly improve the current Planck sensitivity. We interpret our results in the context of the QCD axion and illustrate how the proposed NG searches can improve upon the existing searches for isocurvature power spectrum and bispectrum.

Original languageEnglish
Article number018
JournalJournal of Cosmology and Astroparticle Physics
Volume2024
Issue number12
DOIs
StatePublished - 1 Dec 2024

Funding

FundersFunder number
Simons Foundation
NSF-BSFPHY-2210452, 2021779
US-Israeli BSF2018236
National Science FoundationPHY-2210498
U.S. Department of EnergyDE-SC0013642
Israel Science Foundation1302/19, 1424/23

    Keywords

    • inflation
    • non-gaussianity
    • particle physics - cosmology connection
    • physics of the early universe

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