Rivet analyses

title: ATLAS_2012_I1117704

High jet multiplicity squark and gluino search

Experiment: ATLAS (LHC)

Inspire ID: 1117704

Status: VALIDATED

Authors: - Peter Richardson

References: - Expt page: ATLAS-SUSY-2011-19 - arXiv: 1206.1760

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - BSM signal events at 7000 GeV.

Search for SUSY using events with 6 or more jets in association with missing transverse momentum produced in proton-proton collisions at a centre-of-mass energy of 7 TeV. The data sample has a total integrated luminosity of 4.7 fb$^{-1}$. Distributions in the W and top control regions are not produced, while in addition to the plots from the paper the count of events in the different signal regions is included.

Source code:ATLAS_2012_I1117704.cc

```c++ // -- 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"

include "Rivet/Tools/RivetMT2.hh"

namespace Rivet {

class ATLAS_2012_I1117704 : public Analysis { public:

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

/// Constructor
ATLAS_2012_I1117704()
    : Analysis("ATLAS_2012_I1117704") { }

/// @}

public:

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

/// Book histograms and initialise 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");

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

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

  VetoedFinalState vfs;
  vfs.addVetoPairId(PID::MUON);

  /// Jet finder
  declare(FastJets(vfs, JetAlg::ANTIKT, 0.4), "AntiKtJets04");

  // all tracks (to do deltaR with leptons)
  declare(ChargedFinalState(Cuts::abseta < 3), "cfs");

  /// Book histograms
  book(_etmiss_HT_7j55, "etmiss_HT_7j55", 8, 0., 16.);
  book(_etmiss_HT_8j55, "etmiss_HT_8j55", 8, 0., 16.);
  book(_etmiss_HT_9j55, "etmiss_HT_9j55", 8, 0., 16.);
  book(_etmiss_HT_6j80, "etmiss_HT_6j80", 8, 0., 16.);
  book(_etmiss_HT_7j80, "etmiss_HT_7j80", 8, 0., 16.);
  book(_etmiss_HT_8j80, "etmiss_HT_8j80", 8, 0., 16.);

  book(_hist_njet55, "hist_njet55", 11, 2.5, 13.5);
  book(_hist_njet80, "hist_njet80", 11, 2.5, 13.5);

  book(_count_7j55, "count_7j55", 1, 0., 1.);
  book(_count_8j55, "count_8j55", 1, 0., 1.);
  book(_count_9j55, "count_9j55", 1, 0., 1.);
  book(_count_6j80, "count_6j80", 1, 0., 1.);
  book(_count_7j80, "count_7j80", 1, 0., 1.);
  book(_count_8j80, "count_8j80", 1, 0., 1.);
}


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

  // get the jet candidates
  Jets cand_jets = apply<FastJets>(event, "AntiKtJets04")
                       .jetsByPt(Cuts::pT > 20.0 * GeV && Cuts::abseta < 2.8);

  // candidate muons
  Particles cand_mu;
  Particles chg_tracks = apply<ChargedFinalState>(event, "cfs").particles();
  for (const Particle& mu : apply<IdentifiedFinalState>(event, "muons").particlesByPt()) {
    double pTinCone = -mu.pT();
    for (const Particle& track : chg_tracks) {
      if (deltaR(mu.momentum(), track.momentum()) <= 0.2) pTinCone += track.pT();
    }
    if (pTinCone < 1.8 * GeV) cand_mu.push_back(mu);
  }

  // candidate electrons
  Particles cand_e = apply<IdentifiedFinalState>(event, "elecs").particlesByPt();

  // resolve jet/lepton ambiguity
  Jets recon_jets;
  for (const Jet& jet : cand_jets) {
    // candidates after |eta| < 2.8
    if (fabs(jet.eta()) >= 2.8) continue;
    bool away_from_e = true;
    for (const Particle& e : cand_e) {
      if (deltaR(e.momentum(), jet.momentum()) <= 0.2) {
        away_from_e = false;
        break;
      }
    }
    if (away_from_e) recon_jets.push_back(jet);
  }

  // only keep electrons more than R=0.4 from jets
  Particles recon_e;
  for (const Particle& e : cand_e) {
    bool away = true;
    for (const Jet& jet : recon_jets) {
      if (deltaR(e.momentum(), jet.momentum()) < 0.4) {
        away = false;
        break;
      }
    }
    if (away) recon_e.push_back(e);
  }

  // only keep muons more than R=0.4 from jets
  Particles recon_mu;
  for (const Particle& mu : cand_mu) {
    bool away = true;
    for (const Jet& jet : recon_jets) {
      if (deltaR(mu.momentum(), jet.momentum()) < 0.4) {
        away = false;
        break;
      }
    }
    if (away) 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();

  // now only use recon_jets, recon_mu, recon_e

  // reject events with electrons and muons
  if (!(recon_mu.empty() && recon_e.empty())) {
    MSG_DEBUG("Charged leptons left after selection");
    vetoEvent;
  }

  // calculate H_T
  double HT = 0;
  for (const Jet& jet : recon_jets) {
    if (jet.pT() > 40 * GeV) HT += jet.pT();
  }

  // number of jets
  unsigned int njet55 = 0, njet80 = 0;
  for (unsigned int ix = 0; ix < recon_jets.size(); ++ix) {
    if (recon_jets[ix].pT() > 80. * GeV) ++njet80;
    if (recon_jets[ix].pT() > 55. * GeV) ++njet55;
  }

  if (njet55 == 0) vetoEvent;

  double ratio = eTmiss / sqrt(HT);

  if (ratio > 4.) {
    _hist_njet55->fill(njet55);
    _hist_njet80->fill(njet80);
    // 7j55
    if (njet55 >= 7) _count_7j55->fill(0.5);
    // 8j55
    if (njet55 >= 8) _count_8j55->fill(0.5);
    // 8j55
    if (njet55 >= 9) _count_9j55->fill(0.5);
    // 6j80
    if (njet80 >= 6) _count_6j80->fill(0.5);
    // 7j80
    if (njet80 >= 7) _count_7j80->fill(0.5);
    // 8j80
    if (njet80 >= 8) _count_8j80->fill(0.5);
  }

  if (njet55 >= 7) _etmiss_HT_7j55->fill(ratio);
  // 8j55
  if (njet55 >= 8) _etmiss_HT_8j55->fill(ratio);
  // 8j55
  if (njet55 >= 9) _etmiss_HT_9j55->fill(ratio);
  // 6j80
  if (njet80 >= 6) _etmiss_HT_6j80->fill(ratio);
  // 7j80
  if (njet80 >= 7) _etmiss_HT_7j80->fill(ratio);
  // 8j80
  if (njet80 >= 8) _etmiss_HT_8j80->fill(ratio);
}

/// @}

void finalize() {
  double norm = crossSection() / femtobarn * 4.7 / sumOfWeights();

  scale(_etmiss_HT_7j55, 2. * norm);
  scale(_etmiss_HT_8j55, 2. * norm);
  scale(_etmiss_HT_9j55, 2. * norm);
  scale(_etmiss_HT_6j80, 2. * norm);
  scale(_etmiss_HT_7j80, 2. * norm);
  scale(_etmiss_HT_8j80, 2. * norm);

  scale(_hist_njet55, norm);
  scale(_hist_njet80, norm);

  scale(_count_7j55, norm);
  scale(_count_8j55, norm);
  scale(_count_9j55, norm);
  scale(_count_6j80, norm);
  scale(_count_7j80, norm);
  scale(_count_8j80, norm);
}

private:

/// @name Histograms
/// @{
Histo1DPtr _etmiss_HT_7j55;
Histo1DPtr _etmiss_HT_8j55;
Histo1DPtr _etmiss_HT_9j55;
Histo1DPtr _etmiss_HT_6j80;
Histo1DPtr _etmiss_HT_7j80;
Histo1DPtr _etmiss_HT_8j80;

Histo1DPtr _hist_njet55;
Histo1DPtr _hist_njet80;

Histo1DPtr _count_7j55;
Histo1DPtr _count_8j55;
Histo1DPtr _count_9j55;
Histo1DPtr _count_6j80;
Histo1DPtr _count_7j80;
Histo1DPtr _count_8j80;
/// @}

};

RIVET_DECLARE_PLUGIN(ATLAS_2012_I1117704);

} ```