Relativistic kinematics beyond Special Relativity

Understand

In the context of departures from Special Relativity written as a momentum power expansion in the inverse of an ultraviolet energy scale M, we derive the constraints that the relativity principle imposes between coefficients of a deformed composition law, dispersion relation, and transformation laws, at first order in the power expansion.

• In particular, we find that, at that order, the consistency of a modification of the energy-momentum composition law fixes the modification in the dispersion relation.
• We therefore obtain the most generic modification of Special Relativity that preserves the relativity principle at leading order in 1/M.