Observational constraints on dark matter-dark energy scattering cross section

TL;DR

This paper provides precise observational constraints on the dark matter-dark energy scattering cross section, using multiple cosmological data sets, and finds it to be extremely small, with potential implications for large-scale structure growth.

Contribution

The study offers the first robust observational limits on dark matter-dark energy scattering cross section, highlighting its negligible impact on background cosmology but possible effects on structure formation.

Findings

Scattering cross section constrained to < 10^{-29} cm^2 at 95% CL

Dark matter-dark energy scattering may affect large-scale structure growth

Background cosmology remains unaffected by scattering

Abstract

In this letter, we report precise and robust observational constraints on dark matter-dark energy scattering cross section, using the latest data from cosmic microwave background (CMB) Planck temperature and polarization, baryon acoustic oscillations (BAO) measurements and weak gravitational lensing data from Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). The scattering scenario consists of a pure momentum exchange between the dark components, and we find $\sigma_d < 10^{-29} \, {\rm cm^2}$ at 95\% CL from the joint analysis (CMB + BAO + CFHTLenS), for typical dark matter particle mass of the order 1-10 ${\rm GeV}/c^2$. We notice that the scattering among the dark components may influence the growth of large scale structure in the Universe, leaving the background cosmology unaltered.