Hints of self-interacting dark matter from strong gravitational lensing

Abstract

An analysis of 29 quadruply imaged quasars hints at dark matter halo densities consistent with gravothermal core collapse, a key prediction of self-interacting dark matter. We interpret this evidence through elastic Yukawa scattering, combining lensing with upper limits on the cross-section strength from galaxy clusters and Milky Way satellite evaporation. Favored models have dark matter masses of $20$-$80\mathrm{GeV}$, MeV-scale mediators, and Yukawa-potential strengths near $10^{-3}$, yielding cross-sections of $10^2$--$10^4\mathrm{c}{\mathrm{m}}^2{\mathrm{g}}^{-1}$ at $10\mathrm{km}{\mathrm{s}}^{-1}$. Cosmological, direct and indirect detection bounds on MeV-scale mediators motivate a neutrinophilic scalar dilepton that decays invisibly without Higgs mixing. These results demonstrate how inferences on core collapse constrain dark sector physics.

arXiv commentCompanion paper to JWST Lensed Quasar Dark Matter Survey V; submitted to PRL, comments welcome