Joint Cosmic Microwave Background and Big Bang Nucleosynthesis Constraints on Light Dark Sectors with Dark Radiation

Cara Giovanetti, Mariangela Lisanti, Hongwan Liu, Joshua T. Ruderman

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Dark sectors provide a compelling theoretical framework for thermally producing sub-GeV dark matter, and motivate an expansive new accelerator and direct-detection experimental program. We demonstrate the power of constraining such dark sectors using the measured effective number of neutrino species, Neff, from the cosmic microwave background (CMB) and primordial elemental abundances from big bang nucleosynthesis. As a concrete example, we consider a dark matter particle of arbitrary spin that interacts with the standard model via a massive dark photon, accounting for an arbitrary number of light degrees of freedom in the dark sector. We exclude dark matter masses below ∼4 MeV at 95% confidence for all dark matter spins and dark photon masses. These bounds hold regardless of additional new light, inert degrees of freedom in the dark sector, and for dark matter-electron scattering cross sections many orders of magnitude below current experimental constraints. The strength of these constraints will only continue to improve with future CMB experiments.

Original languageEnglish (US)
Article number021302
JournalPhysical review letters
Volume129
Issue number2
DOIs
StatePublished - Jul 8 2022

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

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