  Extensions to kinetic theory and hydrodynamic models are proposed that
account for the existence of multi-particle contacts. In the presence of
multi-particle contacts (involving elastic, reversible, potential contact
energy), dissipation of the translational (kinetic) energy is reduced and a
class of different models lead to deviations from the classical inelastic hard
sphere (IHS) homogeneous cooling state (HCS), as examined here. The theoretical
results are found to be in perfect agreement with the numerical simulations.
