Limits on the Light Dark Matter–Proton Cross Section from Cosmic Large-Scale Structure

• We set the strongest limits to date on the velocity-independent dark matter (DM)–proton cross section σ for DM masses m=10  keV to 100 GeV, using large-scale structure traced by the Lyman-alpha forest: e.g., a 95% lower limit σ<6×10−30  cm2, for m=100  keV. Our results complement direct detection, which has limited sensitivity to sub-GeV DM. We use an emulator of cosmological simulations, combined with data from the smallest cosmological scales used to date, to model and search for the imprint of primordial DM–proton collisions. Cosmological bounds are improved by up to a factor of 25.

Subject headings

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

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