  Dynamical dark matter (DDM) is a new framework for dark-matter physics in
which the dark sector comprises an ensemble of individual component fields
which collectively conspire to act in ways that transcend those normally
associated with dark matter. Because of its non-trivial structure, this DDM
ensemble --- unlike most traditional dark-matter candidates --- cannot be
characterized in terms of a single mass, decay width, or set of scattering
cross-sections, but must instead be described by parameters which describe the
collective behavior of its constituents. Likewise, the components of such an
ensemble need not be stable so long as lifetimes are balanced against
cosmological abundances across the ensemble as a whole. In this paper, we
investigate the prospects for identifying a DDM ensemble at the LHC and for
distinguishing such a dark-matter candidate from the candidates characteristic
of traditional dark-matter models. In particular, we focus on DDM scenarios in
which the component fields of the ensemble are produced at colliders alongside
some number of Standard-Model particles via the decays of additional heavy
fields. The invariant-mass distributions of these Standard-Model particles turn
out to possess several unique features that cannot be replicated in most
traditional dark-matter models. We demonstrate that in many situations it is
possible to differentiate between a DDM ensemble and a traditional dark-matter
candidate on the basis of such distributions. Moreover, many of our results
also apply more generally to a variety of other extensions of the Standard
Model which involve multiple stable or metastable neutral particles.
