Gluon-decay cascade in AA collisions at the LHC and saturation

Abstract

We extract the energy-dependence of the gluon-jet decay cascade from e^+e^- annihilation data and show that this energy-dependence has power-low behavior for the average transverse momentum of jet bigger than 1 GeV. We show that the observed different power-law energy-dependence of hadron multiplicity in AA compared to pp collisions at the LHC is due to the enhanced gluon-decay effect before hadronization. This effect is more important for AA collisions where the saturation scale is larger than 1 GeV. Here we confront our published predictions in arXiv:1102.2385 for the rapidity distribution of the charged hadron production with the recently released data from the CMS collaboration in AA collisions and show that our predictions is in perfect agreement with the data.