Early-Universe constraints on dark matter-baryon scattering and their implications for a global 21 cm signal

By T. Slatyer, Chih-Liang Wu. Physical Review D, 2018

170 citations recorded by the source corpus.

We present and compare several cosmological constraints on the cross section for elastic scattering between dark matter (DM) and baryons, for cross sections with a range of power-law dependences on the DM-baryon relative velocity $v$, especially focusing on the case of $\sigma \propto v^{-4}$. We study constraints spanning a wide range of epochs in cosmological history, from pre-recombination distortions to the blackbody spectrum and anisotropies of the cosmic microwave background (CMB), to modifications to the intergalactic medium temperature and the resulting 21cm signal, and discuss the allowed signals in the latter channels given the constraints from the former. We improve previous constraints on DM-baryon scattering from the CMB anisotropies, demonstrate via principal component analysis that the effect on the CMB can be written as a simple function of DM mass, and map out the redshifts dominating this signal. We show that given high-redshift constraints on DM-baryon scattering, a $v^{-4}$ scaling of the cross section for light DM would be sufficient to explain the deep 21cm absorption trough recently claimed by the EDGES experiment, if 100% of the DM scatters with baryons. For millicharged DM models proposed to explain the observation, where only a small fraction of the DM interacts, we estimate that a PIXIE-like future experiment measuring CMB spectral distortion could test the relevant parameter space.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a4bb9f6b1f6da7c4d1725e314a39686e70e77011

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Citations in the corpus

Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects (2018, background): “…2018; Hill and Baxter, 2018; Hirano and Bromm, 2018; Kang, 2018; Liu and Slatyer, 2018; Mahdawi and Farrar, 2018; McGaugh, 2018; Mitridate and Podo, 2018; Muñoz and Loeb, 2018; Muñoz et al., 2018; Pospelov et al., 2018; Safarzadeh et al., 2018; Slatyer and Wu, 2018; Witte et al., 2018; Yang, 2018).”
The Simons Observatory: science goals and forecasts (2018, methodology): “…have been used to search for interactions of dark matter particles with masses down to 1 keV (Gluscevic and Boddy 2018; Boddy and Gluscevic 2018; Slatyer and Wu 2018; Xu et al. 2018) – far beyond the reach of current nuclear-recoil based experiments that are optimized to detect weakly…”
Hubble Tension: The Evidence of New Physics (2023, unknown): “2) DM–baryon coupling [334,335]; (3) DE–baryon coupling [336,337]; (4) Interacting neutrinos [338–340]; (4.”
CMB-S4 Science Case, Reference Design, and Project Plan (2019, background): “[280, 281, 274] have searched for interactions that can be parameterized by a power-law dependence of the interaction cross-section on the relative particle velocity, and reported improved limits on a wide range of models.”
PICO: Probe of Inflation and Cosmic Origins (2019, methodology): “This effect has been used to search for evidence of dark-matter–proton scattering over a range of masses, couplings, and interaction models [55–62], to test the possibility of an interacting dark-matter sub-component [61], and to provide consistency tests of dark matter in the context of the anomalo”