  At high energies on a cosmological brane of Randall-Sundrum type, particle
interactions can produce gravitons that are emitted into the bulk and that can
feed a bulk black hole. We generalize previous investigations of such radiating
brane-worlds by allowing for a breaking of Z_2-symmetry, via different bulk
cosmological constants and different initial black hole masses on either side
of the brane. One of the notable features of asymmetry is a suppression of the
asymptotic level of dark radiation, which means that nucleosynthesis
constraints are easier to satisfy. There are also models where the radiation
escapes to infinity on one or both sides, rather than falling into a black
hole, but these models can have negative energy density on the brane.
