Wess-Zumino actions and Dirichlet Boundary Conditions for Super p-branes with Exotic Fractions of Supersymmetry

The general solutions in the models of closed and open superstring and super p-branes with exotic fractions of the N=1 supersymmetry are considered and the spontaneously broken character of the $OSp(1,2M)$ symmetry of the models is established. It is shown that extending these models by Wess-Zumino terms generates the Dirichlet boundary conditions for superstring and super p-branes. Using the generalized Wess-Zumino terms new $OSp(1,2M)$ invariant super p-brane and Dp-brane-like actions preserving $\frac{M-1}{M}$ fraction of supersymmetry are proposed. For M=32 these models suggest new superbrane vacua of M-theory preserving 31 from 32 global supersymmetries.