Distortion in groups of Affine Interval Exchange transformations

In this paper, we study distortion in the group $mathcal A$ of Affine Interval Exchange Transformations (AIET). We prove that any distorted element $f$ of $mathcal A$, has an iterate $f^ k$ that is conjugate by an element of $mathcal A$ to a product of infinite order restricted rotations, with pairwise disjoint supports. As consequences we prove that no Baumslag-Solitar group, $BS(m,n)$ with $vert m vert eq vert n vert$, acts faithfully by elements of $mathcal A$, every finitely generated nilpotent group of $mathcal A$ is virtually abelian and there is no distortion element in $mathcal A_{mathbb Q}$, the subgroup of $mathcal A$ consisting of rational AIETs.