  The accelerated expansion of the universe has been established through
observations of supernovae, the growth of structure, and the cosmic microwave
background. The most popular explanation is Einsteins cosmological constant, or
dynamic variations hereof. A recent paper demonstrated that if dark matter
particles are endowed with a repulsive force proportional to the internal
velocity dispersion of galaxies, then the corresponding acceleration of the
universe may follow that of a cosmological constant fairly closely. However, no
such long-range force is known to exist. A concrete example of such a force is
derived here, by equipping the dark matter particles with two new dark charges.
This result lends support to the possibility that the current acceleration of
the universe may be explained without the need for a cosmological constant.
