Large hierarchy from extra dimensions

We argue that the familiar gauge hierarchy between the fundamental Planck s cale M-PI and the electroweak scale M-W, can be naturally explained in high er dimensional theories with relatively large radii (R-c > 1/M-PI) extra di mensions. In particular, we show that it is possible that the electroweak H iggs mass at high energies is of the order of M-PI, but radiative correctio ns drive it to an infrared stable fixed-point similar to M-W at low energie s thus inducing a large hierarchy without any fine tuning of parameters. (C ) 2000 Elsevier Science B.V. All rights reserved.