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

TL;DR

This paper investigates how gluon decay cascades influence particle production in heavy-ion collisions at the LHC, revealing a power-law energy dependence and confirming predictions with CMS data.

Contribution

It demonstrates the energy dependence of gluon-jet decay cascades from e+e- data and links this to observed multiplicity patterns in AA collisions at the LHC.

Findings

Gluon-jet decay cascade energy dependence follows a power-law for transverse momentum > 1 GeV.

Enhanced gluon decay effects explain the multiplicity differences between AA and pp collisions.

Predictions for rapidity distribution match recent CMS measurements.

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.