  Llight-element abundances probing big bang nucleosynthesis and precision data
from cosmology probing the cosmic microwave background decoupling epoch have
hinted at the presence of extra relativistic degrees of freedom. This is widely
referred to as "dark radiation", suggesting the need for new light states in
the UV completion of the standard model. We provide a brief and concise
overview of the current observational status of such dark radiation and
investigate the interplay between two possible interpretations of the extra
light states: the right-handed partners of three Dirac neutrinos (which
interact with all fermions through the exchange of a new heavy vector meson)
and dark matter particles that were produced through a non-thermal mechanism,
such us late time decays of massive relics. This model ties together
cosmological indications of extra light states and the production of the heavy
vector particle at the LHC.
