Matryoshka Skyrmions

We construct a stable Skyrmion in 3+13+1 dimensions as a sine-Gordon kink inside a domain wall within a domain wall in an O(4)O(4) sigma model with hierarchical mass terms without the Skyrme term. We also find that higher dimensional Skyrmions can stably exist with a help of non-Abelian domain walls in an O(N)O(N) model with hierarchical mass terms without a Skyrme term, which leads to a matryoshka structure of Skyrmions.