# Low-momentum pion enhancement from schematic hadronization of a gluon-saturated initial state

## TL;DR

This paper models early-stage particle production in heavy-ion collisions, showing that gluon overpopulation causes low-momentum pion enhancement, aligning with CERN LHC experimental results.

## Contribution

It introduces a schematic hadronization model linking gluon phase space overpopulation to pion enhancement, providing insights into initial state effects in heavy-ion collisions.

## Key findings

- Gluon overpopulation leads to Bose enhancement in low-momentum gluons.
- Gluon-pion conversion reflects in low-momentum pion enhancement.
- Model aligns with experimental data from CERN LHC ALICE experiment.

## Abstract

We study the particle production in the early stage of the ultrarelativistic heavy-ion collisions. To this end the Boltzmann kinetic equations for gluons and pions with elastic rescattering are considered together with a simple model for the parton-hadron conversion process (hadronisation). It is shown that the overpopulation of the gluon phase space in the initial state leads to an intermediate stage of Bose enhancement in the low-momentum gluon sector which due to the gluon-pion conversion process is then reflected in the final distribution function of pions. This pattern is very similar to the experimental finding of a low-momentum pion enhancement in the ALICE experiment at CERN LHC. Relations to the thermal statistical model of hadron production and the phenomenon of thermal and chemical freeze-out are discussed in this context.