Speaker: Josh Berger, University of Wisconsin-Madison
Abstract: Many models of cold dark matter generate the observed relic abundance by employing dark photons and/or dark Higgs bosons as mediators. In this work, we place constraints on the mediator parameter space by considering nucleosynthesis and CMB spectral distortion constraints. We focus on the limit when the mediators have very weak mixing with the Standard Model. Before their decay, mediator abundance is frozen-in. We find dramatic improvement on the spectral distortion constraints can be generated from a proposed experiment such as PIXIE.