Dominance of virtual Delbruck scattering for the photon emission by nuclei in relativistic electron-nucleus and nucleus-nucleus collisions

摘要

We consider the contribution of virtual Delbruck scattering to the photon emission by nuclei in the collision of two ultra-relativistic nuclei Z(1)Z(2) -> Z(1)Z(2)gamma and electron-nucleus collisions eZ -> eZ gamma, in the photon energy range m E-gamma m gamma, where m is the electron mass and gamma is the Lorentz factor of the colliding nucleus. The discussed process has no infrared divergence. The total cross section is 50 barn for the Pb-Pb collisions at the LHC collider. The spectral distribution obtained is considerably larger than for ordinary nuclear bremsstrahlung in the same photon energy range. (c) 2007 Elsevier B.V. All rights reserved.