The Fox-Wolfram Moment of Jet Production in Relativistic Heavy Ion Collisions

TL;DR

This paper investigates how Fox-Wolfram moments, used to analyze jet production in heavy ion collisions, are affected by the quark-gluon plasma, revealing medium modifications and jet quenching effects through theoretical models.

Contribution

It provides the first theoretical analysis of Fox-Wolfram moments in multi-jet production within relativistic heavy ion collisions, combining Monte Carlo simulations and transport models.

Findings

In Pb+Pb collisions, $H_1^T$ is suppressed at small values and enhanced at large values for two-jet events.

Jet quenching reduces the $H_1^T$ at large values in multi-jet events compared to p+p collisions.

Medium modifications of $H_1^T$ are similar for events with two or more jets.

Abstract

We present the first theoretical investigation of Fox-Wolfram moments (FWMs) for multi-jet production in relativistic heavy ion collisions. In this work, jet productions in p+p collisions are computed with a Monte Carlo event generator SHERPA, while the Linear Boltzmann Transport model is utilized to simulate the multiple scattering of energetic partons in the hot and dense QCD matter. The event-normalized distributions of the lower-order FWM, $H_1^T$ in p+p and Pb+Pb collisions are calculated. It is found that for events with jet number $n_\text{jet} = 2$ the $H_1^T$ distribution in Pb+Pb is suppressed at small $H_1^T$ while enhanced at large $H_1^T$ region as compared to p+p. For events with $n_\text{jet}>2$, the jet number reduction effect due to jet quenching in the QGP decreases the $H_1^T$ distribution at large $H_1^T$ in Pb+Pb relative to p+p. The medium modification of the Fox-Wolfram moment $H_1^T$ for events with $n_\text{jet}\ge 2$ are also presented, which resemble those of events with $n_\text{jet} = 2$. Its reason is revealed through the relative contribution fractions of events with different final-state jet numbers to $H_1^T$.