A Monte Carlo Model for 'Jet Quenching'

TL;DR

This paper introduces JEWEL 1.0, a Monte Carlo simulation that models jet evolution and energy loss in heavy ion collisions, distinguishing between collisional and radiative effects on jet structure.

Contribution

The paper presents a novel Monte Carlo model, JEWEL 1.0, that simulates medium effects on jets and differentiates between collisional and radiative energy loss mechanisms.

Findings

JEWEL accurately reproduces benchmark jet measurements without medium effects.

Medium-induced modifications of jets can be characterized and distinguished.

Characteristic differences in jet fragmentation patterns reveal underlying energy loss processes.

Abstract

We have developed the Monte Carlo simulation program JEWEL 1.0 (Jet Evolution With Energy Loss), which interfaces a perturbative final state parton shower with medium effects occurring in ultra-relativistic heavy ion collisions. This is done by comparing for each jet fragment the probability of further perturbative splitting with the density-dependent probability of scattering with the medium. A simple hadronisation mechanism is included. In the absence of medium effects, we validate JEWEL against a set of benchmark jet measurements. For elastic interactions with the medium, we characterise not only the medium-induced modification of the jet, but also the jet-induced modification of the medium. Our main physics result is the observation that collisional and radiative medium modifications lead to characteristic differences in the jet fragmentation pattern, which persist above a soft background cut. We argue that this should allow to disentangle collisional and radiative parton energy loss mechanisms by measuring the n-jet fraction or a class of jet shape observables.