Background subtraction and jet quenching on jet reconstruction

TL;DR

This paper investigates how background subtraction and jet quenching affect jet reconstruction in heavy-ion collisions, comparing methods and analyzing their impact on observables like dijet asymmetry, using toy models and Monte Carlo simulations.

Contribution

It provides a comparative analysis of background subtraction techniques and assesses the influence of jet quenching on jet observables using Q-PYTHIA simulations.

Findings

Different background subtraction methods impact dijet momentum imbalance.

Q-PYTHIA can reproduce CMS data on missing transverse momentum.

Large angle soft particle emission is indicated by the data.

Abstract

In order to assess the ability of jet observables to constrain the characteristics of the medium produced in heavy-ion collisions at the LHC, we investigate the influence of background subtraction and jet quenching on jet reconstruction, with focus on the dijet asymmetry as currently studied by ATLAS and CMS. Using a toy model, we examine the influence of different background subtraction methods on dijet momentum imbalance and azimuthal distributions. We compare the usual jet-area based background subtraction technique and a variant of the noise-pedestal subtraction method used by CMS. The purpose of this work is to understand what are the differences between the two techniques, given the same event configuration. We analyze the influence of the quenching effect using the Q-PYTHIA Monte Carlo on the previous observables and to what extent Q-PYTHIA is able to reproduce the CMS data for the average missing transverse momentum that seems to indicate the presence of large angle emission of soft particles.