Lower Bound on the Propagation Speed of Gravity from Gravitational Cherenkov Radiation

الأصل · EN

Recently, interesting 4-D Lorentz violating models have been proposed, in which all particles have a common maximum velocity c, but gravity propagates (in the preferred frame) with a different maximum velocity cg ≠ c. We show that the case cg < c is very tightly constrained by the observation of the highest energy cosmic rays. Assuming a galactic origin for the cosmic rays gives a conservative bound of c-cg < 2 × 10⁻¹⁵ c; if the cosmic rays have an extragalactic origin the bound is orders of magnitude tighter, of order c-cg < 2 × 10⁻¹⁹ c.