Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
#include "Rivet/Projections/VetoedFinalState.hh"
#include "Rivet/Projections/VisibleFinalState.hh"

namespace Rivet {


  class ATLAS_2011_CONF_2011_090 : public Analysis {
  public:

    /// @name Constructors etc.
    /// @{

    /// Constructor

    ATLAS_2011_CONF_2011_090()
        : Analysis("ATLAS_2011_CONF_2011_090") { }

    /// @}


  public:

    /// @name Analysis methods
    /// @{

    /// Book histograms and initialize projections before the run
    void init() {

      // projection to find the electrons
      IdentifiedFinalState elecs(Cuts::abseta < 2.47 && Cuts::pT >= 20 * GeV);
      elecs.acceptIdPair(PID::ELECTRON);
      declare(elecs, "elecs");

      // veto region electrons (from 2010 arXiv:1102.2357v2)
      Cut vetocut = Cuts::absetaIn(1.37, 1.52);
      IdentifiedFinalState veto_elecs(vetocut && Cuts::pT > 10 * GeV);
      veto_elecs.acceptIdPair(PID::ELECTRON);
      declare(veto_elecs, "veto_elecs");

      // projection to find the muons
      IdentifiedFinalState muons(Cuts::abseta < 2.4 && Cuts::pT > 10 * GeV);
      muons.acceptIdPair(PID::MUON);
      declare(muons, "muons");

      // Jet finder
      VetoedFinalState vfs;
      vfs.addVetoPairId(PID::MUON);
      declare(FastJets(vfs, JetAlg::ANTIKT, 0.4), "AntiKtJets04");

      // all tracks (to do deltaR with leptons)
      declare(ChargedFinalState(Cuts::abseta < 3.0 && Cuts::pT > 0.5 * GeV), "cfs");

      // for pTmiss
      declare(VisibleFinalState(Cuts::abseta < 4.9), "vfs");

      /// Book histograms
      book(_count_mu_channel, "count_muon_channel", 1, 0., 1.);
      book(_count_e_channel, "count_electron_channel", 1, 0., 1.);
      book(_hist_eTmiss_e, "Et_miss_e", 50, 0., 500.);
      book(_hist_eTmiss_mu, "Et_miss_mu", 50, 0., 500.);
      book(_hist_m_eff_e, "m_eff_e", 60, 0., 1500.);
      book(_hist_m_eff_mu, "m_eff_mu", 60, 0., 1500.);
      book(_hist_m_eff_e_final, "m_eff_e_final", 15, 0., 1500.);
      book(_hist_m_eff_mu_final, "m_eff_mu_final", 15, 0., 1500.);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {


      Particles veto_e = apply<IdentifiedFinalState>(event, "veto_elecs").particles();
      if (!veto_e.empty()) {
        MSG_DEBUG("electrons in veto region");
        vetoEvent;
      }

      Jets cand_jets = apply<FastJets>(event, "AntiKtJets04")
                           .jetsByPt(Cuts::pT > 20 * GeV && Cuts::abseta < 2.8);

      Particles candtemp_e = apply<IdentifiedFinalState>(event, "elecs").particlesByPt();
      Particles candtemp_mu = apply<IdentifiedFinalState>(event, "muons").particlesByPt();
      Particles chg_tracks = apply<ChargedFinalState>(event, "cfs").particles();
      Particles cand_mu;
      Particles cand_e;

      // pTcone around muon track
      for (const Particle& mu : candtemp_mu) {
        double pTinCone = -mu.pT();
        for (const Particle& track : chg_tracks) {
          if (deltaR(mu, track) < 0.2) pTinCone += track.pT();
        }
        if (pTinCone < 1.8 * GeV) cand_mu.push_back(mu);
      }


      // pTcone around electron
      for (const Particle& e : candtemp_e) {
        double pTinCone = -e.pT();
        for (const Particle& track : chg_tracks) {
          if (deltaR(e, track) < 0.2) pTinCone += track.pT();
        }
        if (pTinCone < 0.10 * e.pT()) cand_e.push_back(e);
      }


      // discard jets that overlap with electrons
      Jets cand_jets_2;
      for (const Jet& jet : cand_jets) {
        bool away_from_e = true;
        for (const Particle& e : cand_e) {
          if (deltaR(e, jet) <= 0.2) {
            away_from_e = false;
            break;
          }
        }
        if (away_from_e) cand_jets_2.push_back(jet);
      }

      // only consider leptons far from jet
      Particles recon_e, recon_mu;
      for (const Particle& e : cand_e) {
        bool e_near_jet = false;
        for (const Jet& jet : cand_jets_2) {
          if (inRange(deltaR(e, jet), 0.2, 0.4)) e_near_jet = true;
        }
        if (!e_near_jet) recon_e.push_back(e);
      }

      for (const Particle& mu : cand_mu) {
        bool mu_near_jet = false;
        for (const Jet& jet : cand_jets_2) {
          if (deltaR(mu, jet) < 0.4) mu_near_jet = true;
        }
        if (!mu_near_jet) recon_mu.push_back(mu);
      }

      // pTmiss
      Particles vfs_particles = apply<VisibleFinalState>(event, "vfs").particles();
      FourMomentum pTmiss;
      for (const Particle& p : vfs_particles) {
        pTmiss -= p.momentum();
      }
      double eTmiss = pTmiss.pT();


      // final jet filter
      Jets recon_jets;
      for (const Jet& jet : cand_jets_2) {
        recon_jets.push_back(jet);
      }


      // ==================== observables ====================


      // Njets

      int Njets = 0;
      double pTmiss_phi = pTmiss.phi();
      for (const Jet& jet : recon_jets) {
        if (jet.abseta() < 2.8) Njets += 1;
      }
      if (Njets < 3) {
        MSG_DEBUG("Only " << Njets << " jets w/ eta<2.8 left");
        vetoEvent;
      }

      if (recon_jets[0].pT() <= 60.0 * GeV) {
        MSG_DEBUG("No hard leading jet in " << recon_jets.size() << " jets");
        vetoEvent;
      }
      for (int i = 1; i < 3; ++i) {
        if (recon_jets[i].pT() <= 25 * GeV) {
          vetoEvent;
        }
      }

      for (int i = 0; i < 3; ++i) {
        double dPhi = deltaPhi(pTmiss_phi, recon_jets[i].phi());
        if (dPhi <= 0.2) {
          MSG_DEBUG("dPhi too small");
          vetoEvent;
          break;
        }
      }


      Particles lepton;
      if (recon_mu.empty() && recon_e.empty()) {
        MSG_DEBUG("No leptons");
        vetoEvent;
      }
      else {
        for (const Particle& mu : recon_mu) lepton.push_back(mu);
        for (const Particle& e : recon_e) lepton.push_back(e);
      }

      std::sort(lepton.begin(), lepton.end(), cmpMomByPt);

      double e_id = 11;
      double mu_id = 13;

      // one hard leading lepton cut
      if (lepton[0].abspid() == e_id && lepton[0].pT() <= 25 * GeV) {
        vetoEvent;
      }
      else if (lepton[0].abspid() == mu_id && lepton[0].pT() <= 20 * GeV) {
        vetoEvent;
      }

      // exactly one hard leading lepton cut
      if (lepton.size() > 1) {
        if (lepton[1].abspid() == e_id && lepton[1].pT() > 20 * GeV) {
          vetoEvent;
        }
        else if (lepton[1].abspid() == mu_id && lepton[1].pT() > 10 * GeV) {
          vetoEvent;
        }
      }


      // ==================== FILL ====================


      FourMomentum pT_l = lepton[0].momentum();


      double dPhi = deltaPhi(pT_l.phi(), pTmiss_phi);
      double mT = sqrt(2 * pT_l.pT() * eTmiss * (1 - cos(dPhi)));


      // effective mass
      double m_eff = eTmiss + pT_l.pT() + recon_jets[0].pT() + recon_jets[1].pT() + recon_jets[2].pT();


      // Electron channel signal region

      if (lepton[0].abspid() == e_id) {

        _hist_eTmiss_e->fill(eTmiss);
        _hist_m_eff_e->fill(m_eff);

        if (mT > 100 * GeV && eTmiss > 125 * GeV) {
          _hist_m_eff_e_final->fill(m_eff);
          if (m_eff > 500 * GeV && eTmiss > 0.25 * m_eff) {
            _count_e_channel->fill(0.5);
          }
        }
      }

      // Muon channel signal region

      else if (lepton[0].abspid() == mu_id) {

        _hist_eTmiss_mu->fill(eTmiss);
        _hist_m_eff_mu->fill(m_eff);

        if (mT > 100 * GeV && eTmiss > 125 * GeV) {
          _hist_m_eff_mu_final->fill(m_eff);
          if (m_eff > 500 * GeV && eTmiss > 0.25 * m_eff) {
            _count_mu_channel->fill(0.5);
          }
        }
      }
    }

    /// @}


    void finalize() {
      scale(_hist_eTmiss_e, 10. * 165. * crossSection() / picobarn / sumOfWeights());
      scale(_hist_eTmiss_mu, 10. * 165. * crossSection() / picobarn / sumOfWeights());
      scale(_hist_m_eff_e, 25. * 165. * crossSection() / picobarn / sumOfWeights());
      scale(_hist_m_eff_mu, 25. * 165. * crossSection() / picobarn / sumOfWeights());
      scale(_hist_m_eff_e_final, 100. * 165. * crossSection() / picobarn / sumOfWeights());
      scale(_hist_m_eff_mu_final, 100. * 165. * crossSection() / picobarn / sumOfWeights());
    }

  private:

    /// @name Histograms
    /// @{
    Histo1DPtr _count_e_channel;
    Histo1DPtr _count_mu_channel;

    Histo1DPtr _hist_eTmiss_e;
    Histo1DPtr _hist_eTmiss_mu;

    Histo1DPtr _hist_m_eff_e;
    Histo1DPtr _hist_m_eff_mu;
    Histo1DPtr _hist_m_eff_e_final;
    Histo1DPtr _hist_m_eff_mu_final;


    /// @}
  };


  RIVET_DECLARE_PLUGIN(ATLAS_2011_CONF_2011_090);

}