Black hole chromosphere at the CERN LHC

If the scale of quantum gravity is near a TeV, black holes will be copiouslyproduced at the LHC. In this work we study the main properties of the lightdescendants of these black holes. We show that the emitted partons are closelyspaced outside the horizon, and hence they do not fragment into hadrons invacuum but more likely into a kind of quark-gluon plasma. Consequently, thethermal emission occurs far from the horizon, at a temperature characteristicof the QCD scale. We analyze the energy spectrum of the particles emerging fromthe "chromosphere", and find that the hard hadronic jets are almost entirelysuppressed. They are replaced by an isotropic distribution of soft photons andhadrons, with hundreds of particles in the GeV range. This provides a newdistinctive signature for black hole events at LHC.Comment: Incorporates changes made for the version to be published in Phys. Rev. D. Additional details provided on the effect of the chromosphere in cosmic ray shower