Impact of high-energy tails on granular gas properties.

The velocity distribution function of granular gases in the homogeneous cooling state as well as some heated granular gases decays for large velocities as f proportional to exp(-const x v). That is, its high-energy tail is overpopulated as compared with the Maxwell distribution. At the present time, there is no theory to describe the influence of the tail on the kinetic characteristics of granular gases. We develop an approach to quantify the overpopulated tail and analyze its impact on granular gas properties, in particular on the cooling coefficient. We observe and explain anomalously slow relaxation of the velocity distribution function to its steady state.