HORNED PARTICLES AS THE END-POINT OF HAWKING EVAPORATION

This essay reviews recent developments in the theory of Hawking evapor ation of black holes. Study of near extremal magnetically charged blac k holes using a two plus four dimensional effective field theory has l ed to the concept of homed particles or cornucopion as the endpoint of Hawking evaporation. Horned particles are geometries containing two l arge asymptotic regions connected by microscopic necks. They look like point particles to an observer in any given asymptotic region, but in many ways behave like macroscopic objects. In particular, it is very difficult to pair produce them in external fields and their contributi on to virtual loops is highly suppressed. They can serve as the remnan ts necessary to account for the information apparently lost in Hawking evaporation. The information simply goes into the new asymptotic regi on formed when the black hole collapses and evaporates.