Gravitational Bremsstrahlung in Collisions of Ultrarelativistic Charges in the Five-Dimensional ADD Model

Abstract

Within the five-dimensional ADD model of space-time with compactification radius \(R\), we consider the classical gravitational bremsstrahlung arising from the collision of two ultrarelativistic charges. The collision is governed by the impact parameter \(b\) and the Lorentz factor \(\gamma\). Using the perturbation theory, the total energy, radiated as a gravitational wave, is calculated in the leading order in \(\gamma\), as well as the spectral-angular and polarization characteristics. The radiation is characterized by concentration within a cone of opening angle of order \(1/\gamma\), with the dominant contribution coming from frequencies of order \(\gamma^{2}/b\). The average number of Kaluza–Klein emission modes is estimated to be of the order of \(\gamma R/b\).