  According to a recent paper by Robinson and Wilczek, the leading
gravitational corrections to the running of gauge couplings tend to reduce the
values of the couplings at energies below the gravitational scale, defined to
be the energy above which gravity becomes strongly interacting. If the physical
gravitational scale is sufficiently low, as conjectured in certain
extra-dimension models, this behavior of the gauge couplings can be measured in
future high energy experiments, providing a way to determine where the
gravitational scale lies. We estimate that measurements of the fine structure
constant at the Large Hadron Collider and the proposed International Linear
Collider energies can probe the gravitational scale up to several hundred TeV,
which will be the most stringent test that can be obtained in the conceivable
future.
