Gravitational ultrarelativistic interaction of classical particles in   the context of unification of interactions
  The response of the ultrarelativistic particle with spin in a Schwarzschild field to the gravitomagnetic components as measured by the comoving observer is investigated. The dependence of the particle's spin-orbit acceleration on the Lorentz \gamma - factor and the spin orientation is studied. The concrete circular ultrarelativistic orbit of radius r=3m is considered as a partial solution of the Mathisson-Papapetrou equations and as the corresponding high-energy quantum state of the Dirac particle. Numerical estimates for protons and electrons near black holes are given. A tendency of gravitational and electromagnetic interactions to approach in quantitative terms at ultrarelativistic velocities is discussed 
Roman Plyatsko and Oleksa Bilaniuk