A Superconformal Index for HyperKähler Cones

Abstract: We define an index for $\mathfrak{osp}(4^{*}|4)$ superconformal quantum mechanics on a hyperK\"{a}hler cone. The index is defined on an equivariant symplectic resolution of the cone, which acts as a regulator. We present evidence that the index does not depend on the choice of resolution parameters and encodes information about the spectrum of (semi-) short representations of the superconformal algebra of the unresolved space. In particular, there are two types of multiplet which can be counted exactly using the index. These correspond to holomorphic functions on the cone and to the generators of the Borel-Moore homology on the resolved space respectively. We calculate the resulting index by localisation for a large class of examples.