The Cosmic Microwave Background (CMB) and large-scale structure measurements are powerful tools for probing the properties of neutrinos. If neutrinos interact through physics beyond the Standard Model, these interactions can alter how neutrinos move and cluster in the early universe, leaving detectable imprints in cosmological observables. I will review how such non-standard interactions—including neutrino self-interactions, neutrino–dark matter scattering, neutrino decay into dark radiation, and scenarios involving a tower of neutrino states—affect the CMB and matter power spectrum. These signatures can provide unique constraints on neutrino physics, often beyond the reach of current laboratory experiments.
Yuhsin Tsai, Assistant Professor, University of Notre Dame
Host: Adrian Thompson