  Photons radiated from an evaporating black hole in principle provide complete
information on the particle spectrum of nature up to the Planck scale. If an
evaporating black hole were to be observed, it would open a unique window onto
models beyond the Standard Model of particle physics. To demonstrate this, we
compute the limits that could be placed on the size of a dark sector. We find
that observation of an evaporating black hole at a distance of 0.01 parsecs
could probe dark sector models containing one or more copies of the Standard
Model particles, with any mass scale up to 100 TeV.
