Topics in Black Hole Production

We revisit Voloshin's model of multiple black hole production in trans-Planckian elementary particle collisions in D=4. Our revised computation shows that the cross section to produce N additional black holes is suppressed by 1/s, rather than being enhanced as was originally found. We also review the semiclassical gravity picture of black hole production from hep-th/0409131, making additional comments about the meaning of wavepacket subdivision.