Geometric Dark Matter

Understand

The dark matter, needed for various phenomena ranging from flat rotation curves to structure formation, seems to be not only neutral and long-living but also highly secluded from the ordinary matter.

• Here we show that, metric-affine gravity, which involves metric tensor and affine connection as two independent fields, dynamically reduces, in its minimal form, to the usual gravity plus a massive vector field.
• The vector, which interacts with only the quarks, leptons and gravity, is neutral and long-living (longer than the age of the Universe) when its mass range is $9.4\ {\rm MeV} < M_Y < 28.4\ {\rm MeV}$.
• Its scattering cross section from nucleons, which is some 60 orders of magnitude below the current bounds, is too small to facilitate direct detection of the dark matter.