Non-thermal neutrino-like hot dark matter in light of the $S_8$ tension

Subinoy Das, Anshuman Maharana, Vivian Poulin +1

The $\Lambda$CDM prediction of $S_8\equiv {\sigma }_8({\Omega }_m/0.3{)}^{0.5}$ -- where ${\sigma }_8$ is the root mean square of matter fluctuations on a 8 $h^{-1}$Mpc scale -- once calibrated on Planck CMB data…