ИСТИНА

A classical computation of gravitational bremsstrahlung of point particles in ultra­planckian collisions with impact parameter b is presented. The method is based on the post­linear formalism of General Relativity. The total emitted energy, as well as its angular and frequency distribution are discussed in detail. The massless limit is discussed separately. The particles are described with their trajectories, while the contribution of the leading nonlinear terms of the gravitational action is also taken into account. The old quantum results are reproduced in the zero frequency limit. The radiation efficiency outside a narrow cone of the scattering angle $\alpha$ in the forward and backward directions with respect to the initial particle trajectories is given by $\alpha^2$ and is dominated by radiation with characteristic frequency $1/ \alpha b$. Finally, a comparison of the two classical computations and comparison with previous literature, are discussed.