title: 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≫M(P)) 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 M(P)(2)/E≪M(P) (reminiscent of Hawking radiation), a suppressed fragmentation region, and a reduced rapidity plateau, in broad agreement with recent classical estimates.
authors.affiliation: Dipartimento di Fisica, Università di Firenze and INFN, Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Ciafaloni
authors.affiliation: Dipartimento di Fisica, Università di Firenze and INFN, Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Colferai
authors.affiliation: Collège de France, 11 place M. Berthelot, 75005 Paris, France and Theory Division, CERN, CH-1211 Geneva 23, Switzerland.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Veneziano