Background subtraction and jet quenching on jet reconstruction

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.

4 pages, 3 figures, Proceedings for Hard Probes 2012

References in corpus (6)

• FastJet user manual
• Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at sqrt(S(NN))= 2.76 TeV with the ATLAS Detector at the LHC
• Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV
• Jet momentum dependence of jet quenching in PbPb collisions at sqrt(sNN)=2.76 TeV
• Q-PYTHIA: a medium-modified implementation of final state radiation
• Measurement of event background fluctuations for charged particle jet reconstruction in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV

Cited by in corpus (2)

• Measurement of transverse momentum relative to dijet systems in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV
• Apples to Apples in Jet Quenching: robustness of Machine Learning classification of quenched jets to Underlying Event contamination