D0root version v8.0

• Change Log
• Instructions
• Links
• Known Problems

Change Log

Frank Filthaut re-organized the package so that the SAME code works 
on both TMB and TMBTree data formats. Version 7.2 already had this
functionallity but more work was needed to actually decouple dependencies
and give full access to TMB objects. 
ReadEvent classes had been simplified a lot moving all common methods
(such as Jet Energy Scale corrections) to the base ReadEvent class.

Also, new methods had been added for trigger information and track hit
mask options (such as determining if a track has a hit in layer n)

Below is a description of the main changes for TMBTrees:

• Read Event

  if(!_readEvent->GetEntry(ii)) continue;

  has been replazed by

  if(!_readEvent->Read(ii)) continue;

  All readXXX() methods (such as readTracks(), readMuons(), etc.) are now renamed getXXX().

   readTracks()  -->  getTracks()
   readMuons()   -->  getMuons()
   readVertices()-->  getVertices()
   etc.
  

• Memory Managment

  _readEvent->Clear()

  is NOT longer needed as memory is cleaned up before reading a new event.

• Trigger Information

  Trigger information is accessed through the new D0Trigger object:

  D0Trigger* trigger = _readEvent->getTriggerInfo();

  These are examples to access trigger information:

    bool muonTrigger = trigger->MuonTrigger();
    bool jt_25tt_ng  = triggerInfo->TriggerFired("JT_25TT_NG");
   

• Track Hit Mask

  A new D0HitMask class has been introduced so that it becomes easier to access geometric hit information.
  See d0root_analysis/objects/D0HitMask.h class for the list of available methods.
  

  As an example, in order to check whether a track has a SMT hit in the layer 1, the user should do: bool layer1 = aTrack->GetHitMask().has_layer(1);

• Probabilistic Primary Vertex Selection

  The probabilistic primary vertex selection is done in d0root_btag/algorithm class:

  MBPSelector

  Here is an example of use:

  MBPSelector probabilisticPVSelector(14.00); // provide d0reco version as //argument to use correct PDF. probabilisticPVSelector.InputVertices(pVertices); probabilisticPVSelector.SetTracks(alltracks); probabilisticPVSelector.Compute(); D0Vertex* PV = probabilisticPVSelector.HardScatterVertex(); TObjArray mbVertices = probabilisticPVSelector.MinBiasVertices(mbVertices);

• 2-Pass Primary Vertex Reconstruction

  A new improved Primary Vertex finder is introduced. It is based on a 2-pass algorithm:

  In the first pass, a loose vertex is found around each Z-cluster in order to estimate the beam spot position
  In a second pass, a tight vertex is found around the previous beam estimation.

  Monte Carlo studies showed a factor of 2 resolution improvement with respect to the standard algorithm in DATA.

  The algorithm is instantiated with the same parameters as the previous 1-pass PrimaryVertexGlobalFinder:

  PrimaryVertexGlobalFinder2Pass* pvFinder = new PrimaryVertexGlobalFinder2Pass(0.5, //min track pT 0.5, //max transverse dca [cm] 3.0, //dca significance cut (2nd pass) 2.0, //deltaZ (z-track-clustering) 2, //min number of SMT hits 10. //max \chi^{2} pdof. );

Instructions (TMBTree)

In order to run the script, you first need to create a new release area:

//Create release area
//----------------------------------

kinit

newrel -t p14.03.00 mydir
cd mydir
d0setwa
chmod 777 Maked0root_v8.0.csh
source Maked0root_v8.0.csh

Run analysis code

cd d0root_btag
root runBphysicsAnalysis_TMBtree.C

This command will create an instance of the class BphysicsAnalysis called "b". To see the list of available methods please look at d0root_btag/analysis/BphysicsAnalysis.h

To create a B-rtuple with information about J/Psi, Phi and B vertices, do:

    b->Process_diMuons("myOutputFileName", all_muons, muon_pt, muon_quality);

• "myOutputFileName" is the name of the output root tree.
• all_muons is a boolean variable indicating which tracks are going to be vertexed: true: all tracks; false only tracks matched to muons. By default all_muons = false.
• muon_pt is the minimum global muon pT in GeV/c, by default 1.5 GeV/c.
• muon_quality is the minimum quality, by default 0.

  The Muon quality definition is defined in d0root_analysis/objects/Muon.cpp:

• muon_quality = 0: nseg >= 0
• muon_quality = 1: muon_quality 0 + nseg >= 1
• muon_quality = 2: muon_quality 1 + whits_a > 1 && whits_bc > 2 && shits_a > 0 && shits_bc > 0
• muon_quality = 3: muon_quality 2 + nseg >= 3

In order to open the ROOT-tuple and plot the J/Psi invariant mass and lifetime, do:

 root myOutputFileName.root
 tree->Draw("PSI.mass","PSI.mass>2 && PSI.mass<4")
 tree->Draw("PSI.lifetime","PSI.mass>2.8 && PSI.mass<3.3")

Back to Vertex fitting and finding in ROOT page

Links

• bmixing_reco A very complete package for semileptonic B reconstruction developed by Christos Leonidopoulos within the B-physics group.
• top_analyze A root-tuple maker for Top physics analyses using TMB data format.

Known Problems

• Jets matched to EM objects are not removed.

Please send questions/comments/improvements/modifications to

Back to Vertex fitting and finding in ROOT page