A composite solution to the EDGES anomaly
  Subcomponent millicharged dark matter that cools baryons via Coulomb
interactions has been invoked to explain the EDGES anomaly. However, this model
is in severe tension with constraints from cosmology and stellar emissions. In
this work, we consider the consequences of these millicharged particles
existing in composite blobs. The relevant degrees of freedom at high
temperature are minuscule elementary charges, which fuse at low temperatures to
make up blobs of larger charge. These blobs serve as the degrees of freedom
relevant in cooling the baryons sufficiently to account for the EDGES anomaly.
In such a model, cosmology and stellar constraints (which involve
high-temperature processes) apply only to the feebly-interacting elementary
charges and not to the blobs. This salvages a large range of parameter space
for millicharged blobs that can explain the EDGES anomaly. It also opens up new
parameter space for direct detection, albeit at low momentum transfers.
