Medium-modified average multiplicity and multiplicity fluctuations in jets

TL;DR

This paper models how medium-induced gluon radiation affects the average multiplicity and fluctuations in jets from heavy-ion collisions, revealing modifications due to the quark-gluon plasma.

Contribution

It introduces a toy QCD-inspired model with modified splitting functions to account for medium effects on jet multiplicities and fluctuations.

Findings

Enhanced soft hadron production by a factor of √N_s

Suppressed NLO corrections by 1/√N_s

Comparison with vacuum limits confirms medium effects

Abstract

The energy evolution of average multiplicities and multiplicity fluctuations in 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 enhanced by a factor $\sqrt{N_s}$ while next-to-leading order (NLO) corrections are suppressed by $1/\sqrt{N_s}$, where the parameter $N_s>1$ accounts for the induced-soft gluons in the medium. Our results for such global observables are cross-checked and compared with their limits in the vacuum.