  We revisit possible glimpses of black-hole formation by looking at
ultra-planckian string-string collisions at very high final-state multiplicity.
We compare, in particular, previous results using the optical theorem, the
resummation of ladder diagrams at arbitrary loop order, and the AGK cutting
rules, with the more recent study of $2 \rightarrow N$ scattering at $N \sim s
M_P^{-2} \gg 1$. We argue that some apparent tension between the two approaches
disappears once a reinterpretation of the latter's results in terms of suitably
defined infrared-safe cross sections is adopted. Under that assumption, the
typical final state produced in an ultra-planckian collision does indeed appear
to share some properties with those expected from the evaporation of a black
hole of mass $\sqrt{s}$, although no sign of thermalization is seen to emerge
at this level of approximation.

High Energy Physics - Theory