Emerging Hawking-like radiation from gravitational bremsstrahlung beyond the planck scale

Abstract

We argue that, as a consequence of the graviton's spin-2, its bremsstrahlung in trans-Planckian-energy (E蠑MP) gravitational scattering at small deflection angle can be nicely expressed in terms of helicity-transformation phases and their transfer within the scattering process. The resulting spectrum exhibits deeply sub-Planckian characteristic energies of order MP2/E蠐MP (reminiscent of Hawking radiation), a suppressed fragmentation region, and a reduced rapidity plateau, in broad agreement with recent classical estimates.