Algebraic families of higher dimensional ${\mathbb{A}}^1$-contractible affine varieties non-isomorphic to affine spaces

We construct algebraic families of smooth affine ${\mathbb{A}}^1$-contractible varieties of every dimension $n\ge 4$ over fields of characteristic zero which are non-isomorphic to affine spaces and potential counterexamples to the Zariski Cancellation Problem. We further prove that these families of varieties are also counter examples to the generalized Cancellation problem.