Non-BPS Walls and Their Stability in 5D Supersymmetric Theory

An exact solution of non-BPS multi-walls is found in supersymmetric massive T^\star($\mathbb{C}\mathbb{P}$^1) model in five dimensions. The non-BPS multi-wall solution is found to have no tachyon. Although it is only metastable under large fluctuations, we can give topological stability by considering a model with a double covering of the T^\star($\mathbb{C}\mathbb{P}$^1) target manifold. The {\cal N}=1 supersymmetry preserved on the four-dimensional world volume of one wall is broken by the coexistence of the other wall. The supersymmetry breaking is exponentially suppressed as the distance between the walls increases.