Massimo Bianchi (Roma Tor Vergata U.& INFN, Roma)
Glimpses of black hole formation/evaporation in ultra-planckian string collisions
We revisit possible glimpses of black-hole formation by looking at ultra-planckian string collisions. We compare, in particular, previous results using the optical theorem, the resummation of ladder diagrams, and the AGK cutting rules, with the more recent study of high-multiplicity scattering in the `classicalization' approach. In order to reconcile the two approaches we argue that a reinterpretation of the results in the latter is needed. 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 equal to a fraction of the center of mass energy, although no compelling sign of thermalization is seen to emerge at this level of approximation.