SUPERSYMMETRY BREAKDOWN AT A HIDDEN WALL

We consider hidden sector supersymmetry breakdown in the strongly coup led heterotic Es x Es theory of Horava and Witten. Using effective fie ld theory methods in four dimensions, we can show hat gravitational in teractions induce soft breaking terms in the observable sector that ar e of order of the gravitino mass. We apply these methods to the mechan ism of gaugino condensation at the hidden wall. Although the situation is very similar to the weakly coupled case, there is a decisive diffe rence concerning the observable sector gaugino mass; with desirable ph enomenological as well as cosmological consequences. (C) 1998 Elsevier Science B.V.