Sensitivity to Dark Sector Scales from Gravitational Wave Signatures
  We consider gravitational wave signals produced by a first-order phase
transition in a theory with a generic renormalizable thermal effective
potential of power law form. We find the frequency and amplitude of the
gravitational wave signal can be related in a straightforward manner to the
parameters of the thermal effective potential. This leads to a general
conclusion; if the mass of the dark Higgs is less than 1% of the dark Higgs
vacuum expectation value, then the gravitational wave signal will be
unobservable at all upcoming and planned gravitational wave observatories.
