Title: Waist size for cusps in hyperbolic 3-manifolds II,
Abstract: The waist size of a cusp in an orientable hyperbolic 3-manifold is the length
of the shortest nontrivial curve generated by a parabolic isometry in the
maximal cusp boundary. Previously, it was shown that the smallest possible
waist size, which is 1, is realized only by the cusp in the figure-eight knot
complement. In this paper, it is proved that the next two smallest waist sizes
are realized uniquely for the cusps in the $5_2$ knot complement and the
manifold obtained by (2,1)-surgery on the Whitehead link. One application is an
improvement on the universal upper bound for the length of an unknotting tunnel
in a 2-cusped hyperbolic 3-manifold.