MuonAnalyzer.cc

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#include "CommonTools/UtilAlgos/interface/TFileService.h"
#include "DataFormats/Math/interface/LorentzVector.h"
#include "DataFormats/PatCandidates/interface/Muon.h"
#include "FWCore/Framework/interface/EDAnalyzer.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/MakerMacros.h"
#include "FWCore/ServiceRegistry/interface/Service.h"

#include "TH1I.h"
#include "TH1F.h"
#include "TH2F.h"

class ExampleMuonAnalyzer : public edm::EDAnalyzer {
public:
  ExampleMuonAnalyzer(const edm::ParameterSet &pset);

  ~ExampleMuonAnalyzer() override;

  // Operations

  void analyze(const edm::Event &event, const edm::EventSetup &eventSetup) override;

  void beginJob() override;
  void endJob() override;

protected:
private:
  edm::EDGetTokenT<pat::MuonCollection> theMuonToken;

  // Histograms
  TH1I *hNMuons;
  TH1F *hPtRec;
  TH2F *hPtReso;
  TH1F *hEHcal;

  TH1I *hMuonType;
  TH1F *hPtSTATKDiff;

  // ID
  TH1F *hMuCaloCompatibility;
  TH1F *hMuSegCompatibility;
  TH1I *hChamberMatched;
  TH1I *hMuIdAlgo;

  // Isolation
  TH1F *hMuIso03SumPt;
  TH1F *hMuIso03CaloComb;

  TH1F *h4MuInvMass;
};

using namespace std;
using namespace edm;

ExampleMuonAnalyzer::ExampleMuonAnalyzer(const ParameterSet &pset) {
  theMuonToken = consumes<pat::MuonCollection>(pset.getParameter<InputTag>("MuonCollection"));
}

ExampleMuonAnalyzer::~ExampleMuonAnalyzer() {}

void ExampleMuonAnalyzer::beginJob() {
  // Book histograms
  edm::Service<TFileService> fileService;
  hPtRec = fileService->make<TH1F>("pT", "p_{T}^{rec}", 250, 0, 120);
  hPtReso = fileService->make<TH2F>("pT_Reso", "(p_{T}^{rec}-p_{T}^{sim})/p_{T}^{sim}", 250, 0, 120, 100, -0.2, 0.2);
  hNMuons = fileService->make<TH1I>("NMuons", "Number of muons per event", 20, 0, 20);

  hEHcal = fileService->make<TH1F>("EHCal", "Energy deposit in HCAL", 100, 0, 10);

  // ID
  hMuonType = fileService->make<TH1I>("MuonType", "Type of Muons", 5, 1, 6);
  hPtSTATKDiff = fileService->make<TH1F>("DiffPt_STA_TK", "p^{TK}_{T}-p^{STA}_T", 200, -50, 50);
  hMuCaloCompatibility = fileService->make<TH1F>("CaloCompatibility", "Muon HP using Calorimeters only", 100, 0, 1);
  hMuSegCompatibility = fileService->make<TH1F>("SegmentCompatibility", "Muon HP using segments only", 100, 0, 1);
  hChamberMatched = fileService->make<TH1I>("NumMatchedChamber", "Number of matched chambers", 7, 0, 7);
  hMuIdAlgo = fileService->make<TH1I>("MuonIDSelectors", "Results of muon id selectors", 13, 0, 13);

  // Isolation
  hMuIso03SumPt = fileService->make<TH1F>("MuIso03SumPt", "Isolation #Delta(R)=0.3: SumPt", 200, 0, 10);
  hMuIso03CaloComb =
      fileService->make<TH1F>("MuIso03CaloComb", "Isolation #Delta(R)=0.3: 1.2*ECAL+0.8HCAL", 200, 0, 10);

  // 4Mu invariant mass
  h4MuInvMass = fileService->make<TH1F>("InvMass4MuSystem", "Invariant mass of the 4 muons system", 200, 0, 500);
}

void ExampleMuonAnalyzer::endJob() {}

void ExampleMuonAnalyzer::analyze(const Event &event, const EventSetup &eventSetup) {
  // Get the Muon collection
  Handle<pat::MuonCollection> muons;
  event.getByToken(theMuonToken, muons);

  // How many muons in the event?
  hNMuons->Fill(muons->size());

  pat::MuonCollection selectedMuons;

  // Let's look inside the muon collection.
  for (pat::MuonCollection::const_iterator muon = muons->begin(); muon != muons->end(); ++muon) {
    // pT spectra of muons
    hPtRec->Fill(muon->pt());

    // what is the resolution in pt? Easy! We have the association with generated information
    //    cout<<muon->pt()<<" "<<muon->genParticle()->pt()<<endl;
    if (muon->genLepton() != nullptr) {
      double reso = (muon->pt() - muon->genLepton()->pt()) / muon->genLepton()->pt();
      hPtReso->Fill(muon->genLepton()->pt(), reso);
    }

    // What is the energy deposit in HCal?
    if (muon->isEnergyValid())
      hEHcal->Fill(muon->calEnergy().had);

    // Which type of muons in the collection?
    if (muon->isStandAloneMuon())
      if (muon->isGlobalMuon())
        if (muon->isTrackerMuon())
          hMuonType->Fill(1);  // STA + GLB + TM
        else
          hMuonType->Fill(2);  // STA + GLB
      else if (muon->isTrackerMuon())
        hMuonType->Fill(3);  // STA + TM
      else
        hMuonType->Fill(5);  // STA
    else if (muon->isTrackerMuon())
      hMuonType->Fill(4);  // TM

    // ...mmm I want to study the relative resolution of the STA track with respect to the Tracker track.
    // or I want to look at a track stab
    if (muon->isGlobalMuon()) {
      double diff = muon->innerTrack()->pt() - muon->standAloneMuon()->pt();
      hPtSTATKDiff->Fill(diff);
    }

    // Muon ID quantities

    // Muon in CMS are usually MIP. What is the compatibility of a muon HP using only claorimeters?
    if (muon->isCaloCompatibilityValid())
      hMuCaloCompatibility->Fill(muon->caloCompatibility());

    // The muon system can also be used just as only for ID. What is the compatibility of a muon HP using only calorimeters?
    hMuSegCompatibility->Fill(muon::segmentCompatibility(*muon));

    // How many chambers have been associated to a muon track?
    hChamberMatched->Fill(muon->numberOfChambers());
    // If you look at MuonSegmentMatcher class you will see a lot of interesting quantities to look at!
    // you can get the list of matched info using matches()

    // Muon ID selection. As described in AN-2008/098
    if (muon::isGoodMuon(*muon, muon::All))  // dummy options - always true
      hMuIdAlgo->Fill(0);
    if (muon::isGoodMuon(*muon, muon::AllStandAloneMuons))  // checks isStandAloneMuon flag
      hMuIdAlgo->Fill(1);
    if (muon::isGoodMuon(*muon, muon::AllTrackerMuons))  // checks isTrackerMuon flag
      hMuIdAlgo->Fill(2);
    if (muon::isGoodMuon(*muon, muon::TrackerMuonArbitrated))  // resolve ambiguity of sharing segments
      hMuIdAlgo->Fill(3);
    if (muon::isGoodMuon(*muon, muon::AllArbitrated))  // all muons with the tracker muon arbitrated
      hMuIdAlgo->Fill(4);
    if (muon::isGoodMuon(*muon, muon::GlobalMuonPromptTight))  // global muons with tighter fit requirements
      hMuIdAlgo->Fill(5);
    if (muon::isGoodMuon(*muon, muon::TMLastStationLoose))  // penetration depth loose selector
      hMuIdAlgo->Fill(6);
    if (muon::isGoodMuon(*muon, muon::TMLastStationTight))  // penetration depth tight selector
      hMuIdAlgo->Fill(7);
    if (muon::isGoodMuon(*muon, muon::TM2DCompatibilityLoose))  // likelihood based loose selector
      hMuIdAlgo->Fill(8);
    if (muon::isGoodMuon(*muon, muon::TM2DCompatibilityTight))  // likelihood based tight selector
      hMuIdAlgo->Fill(9);
    if (muon::isGoodMuon(*muon, muon::TMOneStationLoose))  // require one well matched segment
      hMuIdAlgo->Fill(10);
    if (muon::isGoodMuon(*muon, muon::TMOneStationTight))  // require one well matched segment
      hMuIdAlgo->Fill(11);
    if (muon::isGoodMuon(*muon,
                         muon::TMLastStationOptimizedLowPtLoose))  // combination of TMLastStation and TMOneStation
      hMuIdAlgo->Fill(12);
    if (muon::isGoodMuon(*muon,
                         muon::TMLastStationOptimizedLowPtTight))  // combination of TMLastStation and TMOneStation
      hMuIdAlgo->Fill(13);

    // Isolation variables. There are many type of isolation. You can even build your own combining the output of
    // muon->isolationR03(). E.g.: 1.2*muon->isolationR03().emEt + 0.8*muon->isolationR03().hadEt
    // *** WARNING *** it is just an EXAMPLE!
    if (muon->isIsolationValid()) {
      hMuIso03CaloComb->Fill(1.2 * muon->isolationR03().emEt + 0.8 * muon->isolationR03().hadEt);
      hMuIso03SumPt->Fill(muon->isolationR03().sumPt);
    }

    // OK, let see if we understood everything.
    // Suppose we are searching for H->ZZ->4mu.
    // In mean the 4 muons have/are:
    // high pt (but 1 out of 4 can be at quite low pt)
    // isolated
    // so, we can make some requirements
    if (muon->isolationR03().sumPt < 0.2) {
      if (muon->isGlobalMuon() || muon::isGoodMuon(*muon, muon::TM2DCompatibilityLoose) ||
          muon::isGoodMuon(*muon, muon::TMLastStationLoose))
        selectedMuons.push_back(*muon);
    }
  }

  if (selectedMuons.size() == 4) {
    reco::Candidate::LorentzVector p4CM;
    for (pat::MuonCollection::const_iterator muon = selectedMuons.begin(); muon != selectedMuons.end(); ++muon) {
      p4CM = p4CM + muon->p4();
    }
    h4MuInvMass->Fill(p4CM.mass());
  }
}
DEFINE_FWK_MODULE(ExampleMuonAnalyzer);