Medium-modified evolution of multiparticle production in jets in heavy-ion collisions

TL;DR

This paper investigates how medium modifications in heavy-ion collisions affect multiparticle production in jets, revealing enhanced soft gluon radiation and challenges in perturbative series convergence.

Contribution

It introduces a toy QCD-inspired model with medium-modified splitting functions to analyze jet multiplicities and fluctuations in heavy-ion collisions.

Findings

Soft hadron production is enhanced by √N_s in the medium.

Next-to-leading order corrections are suppressed by 1/√N_s.

Medium-induced soft gluons significantly impact perturbative series convergence.

Abstract

The energy evolution of medium-modified average multiplicities and multiplicity fluctuations in quark and gluon jets produced in heavy-ion collisions is investigated from a toy QCD-inspired model. In this model, we use modified splitting functions accounting for medium-enhanced radiation of gluons by a fast parton which propagates through the quark gluon plasma. The leading contribution of the standard production of soft hadrons is found to be enhanced by the factor $\sqrt{N_s}$ while next-to-leading order (NLO) corrections are suppressed by $1/\sqrt{N_s}$, where the nuclear parameter $N_s>1$ accounts for the induced-soft gluons in the hot medium. The role of next-to-next-to-leading order corrections (NNLO) is studied and the large amount of medium-induced soft gluons is found to drastically affect the convergence of the perturbative series. Our results for such global observables are cross-checked and compared with their limits in the vacuum and a new method for solving the second multiplicity correlator evolution equations is proposed.