Emerging Jet Analysis

Group members: Kevin Graham, Mohsen Naseri, Jesse A. Heilman, Ian Ramirez Berend, Brandon Death, Jeremie Harmond Lepage Bourbonnais


One of the novel search strategies for new physics at the LHC are emerging jets that dominantly compose of displaced tracks and have many different vertices within the jet cone. The motivations for detailed studies of this unconventioal signature is numerous. Such new objects arise naturally in many models of dark matter with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. In this work, we perform a detailed study for a benchmark signal with two regular and two emerging jets. This analysis is based on reconstructing calorimeter jets with no prompt tracks from the interaction point.

activities of the top-reconstruction sub-group

activities of the top-reconstruction sub-group

Main Analysis Framework

The main analysis framework is based on xAODAnaHelpers package with set of common EventLoop algorithms and C++ classes designed to perform basic event/ object selection, calibration, and object corrections. It can also handle output flat ntuples and different level of systematics sources. Each step of the analysis chain is performed by a standard EL::Algorithm which employ TStore to pass information to the Algos down the chain. The final events can be stored as TTree or histograms. This package make use of minimal wrapper for CP tools to help users to properly configure the modules and connect the full chain without much effort. In addition to standard algorithms, more modules are also defined to do some specific jobs using corresponding derived classes which inherit properties from the base xAODAnaHelpers classes.

xAODAnaHelpers and EJsAnalysis codes to produce ntuples

Here you find the most important C++ codes for producing ntuples and making histograms. As an example, first inspect confing files to run specific jobs either making Ntuples or histograms. The ntuples are produced using the following modules:

xAH Algorithms

  • Event Selection: BasicEventSelection(first algorthem in chain): Performs very basic event selection/processing GRL, PRW, trigger selection, event cleaning, PV cut, etc.

  • Object calibration: Jet calibrator: Performs jet calibration, jet uncertainties, jet cleaning (decoration). This modules saves new containers for nominal (calibrated) collection and each systematic variation to be passed down algorithm chain.

  • Object selection: JetSelector, TrackSelector, TruthSelector: Selects jets, tracks, and truth particles according to user selection.

EJs Algorithms

  • VrtSecInclusive DV selection: SecondaryVertexSelector
After running the ntuple producer, three versions of vertex variables are saved based on different stages of track filtering. The nominal case, with VsiBonsai track trimming, including removal of bad-d0 associated tracks to correct φ asymmetry, is represented by branches with no extra suffix (i.e. secVtx_mass). The clean case, with removal of bad-d0 associated tracks only and no other track trimming applied, is represented by branches with the clean suffix (i.e. secVtx_mass_clean). The base case, with no track trimming of any kind, is represented by branches with the bare suffix (i.e. secVtx_mass_bare). The vertex kinematic properties are calculated with the VSI Bonsai toolkit using track parameters with respect to the displaced vertex.

  • Object matching: ObjectMatcher

Thin module is employed to perform matching between different physics objects and between physics + truth objects and decorates objects accordingly for later access.

  • Analysis selection: EJsxAODAnalysis

We use this module to apply actual analysis selections i.e. define signal, validation, and control regions, define Emerging Jet objects, select signal events, etc.

  • Ntuple making: EJsMiniNtuple

This wrapper algorithm is used to make and output TTree(s) using EJsHelpTreeBase class.

  • Histogramming: EJsNtupleToHists

This wrapper algorithm can be used to make and output histograms from input ntuple using EJsHistogramManager class

Hierarchy relationship between modules

Main development now within xAODAnaHelpers:

Inspecting the definition of samples, cuts, and plots

Model AModel BModel CModel DModel E
10GeV 4GeV 20GeV 40GeV 1.6GeV
20GeV 8GeV 40GeV 80GeV 3.2GeV
5GeV 2GeV 10GeV 20GeV 0.8GeV
600, 1000, 1400 GeV
0.5, 1, 2, 20, 150, 300; 1, 2, 5, 75, 150, 300; 2, 5, 20, 75, 150 300 mm

Testing ntuple producer

Quickly testing the cut flow on a signal sample gives:

Make some plots

The histogram_local.sh file can be used to produce the relevant modules on top of the ntuple scripts. To get our first sets of plots, we can do

./ histogram_local.sh

A word of caution: The following commands were tested to work properly in the "bash" shell. In case you use a different shell, slight alterations might be needed.

Common flags for plotting

Introduced for MC 16 samples

sample ROOT color
Model A kBlue-2
Model B kGreen-2
Model C kOrange-3
Model D kRed-6
Model E kCyan-6
QCD kViolet+5
Inclusive Signal kBlack

Carleton Analysis Framework

To be filled.

Code explenation


  • LHC Cross Section Working Group:
  • * Production Cross Sections at √s =* 13 TeV :
  • * Branching Ratios and Total Decay* Widths:

Important links

Carleton Page

Carleton Meetings

Our meetings currently take place weekly on Fridays at 11:00 am EST

Past Meetings:

Combined Performance Page

Cross Sections

Physics Groups

More Useful Links

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf ANA-EXOT-2018-20-INT1-2.pdf r1 manage 403.9 K 2020-04-27 - 20:12 MohsenNaseri  
Unknown file formatdocx EJsAnalysis_Event_Selection_Cutflow.docx r1 manage 541.4 K 2020-12-03 - 00:31 BrandonDouglasDeath  
PNGpng EmergingSignature.png r1 manage 746.5 K 2020-04-16 - 23:38 MohsenNaseri  
PNGpng FeynmanDiagram.png r1 manage 71.7 K 2020-04-17 - 04:57 MohsenNaseri  
PDFpdf Grid_Authorization_Guide.pdf r1 manage 164.6 K 2020-06-12 - 20:11 JeremieHarmondLepageBourbonnais  
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Topic revision: r20 - 2020-12-03 - BrandonDouglasDeath
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