Hard Bremsstrahlung photons from graviton exchange
  We review photon Bremsstrahlung in extra-dimensional models with massive gravitons. The photon spectrum is harder than in the Standard Model. In the RS scenario, radiative return to gravitons below the c.m. energy can lead to a considerable increase of the cross section. 
T. Buanes, E.W. Dvergsnes, P. Osland