Comparing the MARTINI and CUJET models for jet-quenching: Medium modification of jets and jet substructure

TL;DR

This paper compares two jet-quenching models, CUJET and MARTINI, within the JETSCAPE framework, analyzing their predictions against experimental data on jet spectra and substructure to understand medium modifications in quark-gluon plasma.

Contribution

It provides a direct, systematic comparison of CUJET and MARTINI models for jet quenching using a unified simulation framework, highlighting their similarities and differences.

Findings

Models broadly agree on nuclear modification factors for charged hadrons and jets.

Systematic differences observed in fragmentation functions and jet shapes.

Jet $R_{AA}$ varies with cone size, indicating model-dependent medium modifications.

Abstract

Jets produced by the initial hard scattering in heavy ion collision events lose energy due to interactions with the color-deconfined medium formed around them: the quark-gluon plasma (QGP). Jet-medium interactions constitute an important theoretical and experimental field for studies of QGP, and various models with different assumptions have been proposed to describe them. A fair and direct comparison of these models requires that all other aspects of the simulation be fixed, which is achieved in this work by relying on the JETSCAPE framework. We employ JETSCAPE to directly and comprehensively compare two successful energy loss models: CUJET and MARTINI. We compare the models with the results of measurements of jet spectra and substructure observables. With the strong coupling tuned separately, we find that the two models broadly agree with each other in nuclear modification factors for charged hadrons and jets with cone size $R=0.4$. Systematic differences are reported in fragmentation functions, jet shape, and cone size dependent jet $R_{\mathrm{AA}}$.