  The vortex glass state formed by magnetic flux lines in a type-II
superconductor is shown to possess non-trivial three-body correlations. While
such correlations are usually difficult to measure in glassy systems, the
magnetic fields associated with the flux vortices allow us to probe these via
muon-spin rotation measurements of the local field distribution. We show via
numerical simulations and analytic calculations that these observations provide
detailed microscopic insight into the local order of the vortex glass and more
generally validate a theoretical framework for correlations in glassy systems.
