Exploring dark matter microphysics with galaxy surveys

TL;DR

This paper demonstrates that upcoming galaxy surveys like DESI can significantly improve constraints on dark matter microphysics, specifically DM-neutrino interactions, surpassing current CMB experiment capabilities and potentially leading to discoveries.

Contribution

It shows that galaxy clustering surveys can effectively probe dark matter microphysics and detect deviations from standard cosmology, especially in DM-neutrino scattering scenarios.

Findings

DESI could constrain DM-neutrino interactions an order of magnitude better than Planck.

Future CMB experiments like COrE+ will not significantly improve current constraints.

Galaxy surveys have the potential to detect effects previously only accessible via simulations.

Abstract

We use present cosmological observations and forecasts of future experiments to illustrate the power of large-scale structure (LSS) surveys in probing dark matter (DM) microphysics and unveiling potential deviations from the standard $\Lambda$CDM scenario. To quantify this statement, we focus on an extension of $\Lambda$CDM with DM-neutrino scattering, which leaves a distinctive imprint on the angular and matter power spectra. After finding that future CMB experiments (such as COrE+) will not significantly improve the constraints set by the Planck satellite, we show that the next generation of galaxy clustering surveys (such as DESI) could play a leading role in constraining alternative cosmologies and even have the potential to make a discovery. Typically we find that DESI would be an order of magnitude more sensitive to DM interactions than Planck, thus probing effects that until now have only been accessible via $N$-body simulations.