C:3. Is there a unified framework?
At the energies currently probed by Particle Physics experiments, the effect of the gravitational force is tiny in comparison to the other two forces (electroweak, strong). The apparent weakness of gravity on the quantum scale is a mystery. One explanation why gravity is so weak in our 4-dimensional space-time world is that our Universe exists as part of a higher-dimensional structure.
There are additional spatial dimensions in which only gravity acts wherein the gravitational flux is dissipated. It may be possible to infer the presence of macroscopic extra dimensions from cosmological observations, or from precision measurements of gravity. If the extra dimensions are microscopic, high-energy particle accelerators and cosmic-ray experiments are the only ways to detect them e.g. via the production of rapidly evaporating microscopic black holes.
The unification of forces requires the identification of new symmetries that will explain the pattern of fundamental particles. Such symmetries can be crudely probed by the current experiments but more precise experiments will be necessary to understand any new physics discovered at the L
HC.