Non-BPS instability in heterotic M-theory

We study the warped geometry of heterotic M-theory in five dimensions where five-branes are included in the bulk. Five-branes wrapping holomorphic cur ves lead to BPS configurations where the junction conditions are automatica lly satisfied. We consider five-branes wrapped around non-supersymmetric cy cles and show that the configuration is unstable. We describe explicitly th e resulting time-dependent geometry where the bulk five-branes move towards the Horava-Witten boundary walls. The five-branes collide with the boundar y walls in a finite time resulting in the restoration of supersymmetry. (C) 2001 Published by Elsevier Science B.V.