Rivet analyses

title: ATLAS_2018_I1667046

Search for R-parity-violating SUSY in multi-jet final states at 13 TeV

Experiment: ATLAS (LHC)

Inspire ID: 1667046

Status: VALIDATED

Authors: - Shalini Epari - Andy Buckley

References: - Expt page: ATLAS-SUSY-2016-22 - Phys. Lett. B 785 (2018) 136 - arXiv: 1804.03568 - DOI:10.1016/j.physletb.2018.08.021

Beams: p+ p+

Beam energies: (6500.0, 6500.0)GeV

Run details: - BSM signal events

This search uses 36.1/fb of data collected by the ATLAS detector in proton-proton collisions with a center-of-mass energy of $\sqrt{s}=13$ TeV at the LHC. The analysis is performed using requirements on the number of jets and the number of jets tagged as containing a $b$-hadron, as well as a topological observable formed by the scalar sum of masses of large-radius jets in the event. No significant excess above the expected Standard Model background was observed.

Source code:ATLAS_2018_I1667046.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Tools/Cutflow.hh"

namespace Rivet {

/// Search for R-parity-violating SUSY in multi-jet final states at 13 TeV class ATLAS_2018_I1667046 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2018_I1667046);


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

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

  // Projections
  const FinalState fs(Cuts::abseta < 4.9);
  declare("SmallRJ", FastJets(fs, JetAlg::ANTIKT, 0.4));
  declare("LargeRJ", FastJets(fs, JetAlg::ANTIKT, 1.0));

  // Book histograms
  book(_h_sigmaM, "sigmaM", 50, 200, 2000);
  book(_h_modeta, "ModEta12", 42, 0, 4.2);

  // Cutflows
  book(_flows, {"CutFlow1", "CutFlow2"},
       {{"NJet >= 4 ", "Delta12 < 1.4", "PJet1 > 400 GeV", "M SumJ > 1.0 ", "NbJet > 0",
         "M SumJ > 1.0  & NbJet > 0"},
        {"NJet >= 4 ", "Delta12 < 1.4", "NJet >= 5 ", "M SumJ > 0.8 ", "NbJet > 0",
         "M SumJ > 0.8  & NbJet > 0"}});
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  _flows->groupfillinit();

  // Trim large-R jets and apply cuts
  Jets LRJ_old = apply<FastJets>(event, "LargeRJ").jetsByPt(Cuts::abseta < 4.9);
  Jets LRJJ;
  fastjet::Filter trimmer(fastjet::JetDefinition(fastjet::kt_algorithm, 0.2),
                          fastjet::SelectorPtFractionMin(0.05));
  for (Jet& j : LRJ_old) LRJJ.push_back(trimmer(j));
  Jets LRJ = iselect(LRJJ, Cuts::abseta < 2.0 && Cuts::pT > 200 * GeV);
  if (LRJ.size() < 4) vetoEvent;
  LRJ = sortByPt(LRJ); // sorting for constructing sigmaM

  // Small R jets need to pass some cuts + need to be BTagged.
  const Jets SRJ = apply<FastJets>(event, "SmallRJ").jetsByPt(Cuts::abseta < 2.5 && Cuts::pT > 50 * GeV);
  Jets BT_SRJ = select(SRJ, hasBTag(Cuts::pT > 5 * GeV));
  const int tagg = (BT_SRJ.size() == 0) ? 1 : 0; //if there are no B-TAGGED jets are present, tagg = 1.

  // Now to find B-MATCHED Large R Jets: extra step, not useful for SR regions!
  const Jets BM_LRJ = selectIfAnyDeltaRLess(LRJ, BT_SRJ, 1.0);


  // Now to build observables SigmaM and deltaEta
  // Add mass of leading four large R jets,
  double sigmaM = 0.0;
  for (const Jet& j : head(LRJ, 4)) sigmaM += j.mass();
  _h_sigmaM->fill(sigmaM);

  // Build deta between two leading large-R jets
  const double delta_eta = fabs(deltaEta(LRJ[0], LRJ[1]));
  _h_modeta->fill(delta_eta);

  // CutFlow1
  if (LRJ.size() >= 4) {
    _flows->fillnext("CutFlow1");
    if (delta_eta < 1.4) {
      _flows->fillnext("CutFlow1");
      if (LRJ[0].pT() > 400 * GeV) {
        _flows->fillnext("CutFlow1");
        if (sigmaM > 1000 * GeV) {
          _flows->fillnext("CutFlow1");
        }
        if (tagg == 0) {
          _flows->fillnext("CutFlow1");
          if (sigmaM > 1000 * GeV) {
            _flows->fillnext("CutFlow1");
          }
        } //end of btagg loop
      } //end of pT loop
    } //end of delta loop
  } //end of Njet>4 loop

  // CutFlow2
  if (LRJ.size() >= 4) {
    _flows->fillnext("CutFlow2");
    if (delta_eta < 1.4) {
      _flows->fillnext("CutFlow2");
      if (LRJ.size() >= 5) {
        _flows->fillnext("CutFlow2");
        if (sigmaM > 800 * GeV) {
          _flows->fillnext("CutFlow2");
        }
        if (tagg == 0) {
          _flows->fillnext("CutFlow2");
          if (sigmaM > 800 * GeV) {
            _flows->fillnext("CutFlow2");
          }
        } //end of btagg loop
      } //Njet>5 loop
    } //end of delta loop
  } //Njet>4 loop
}


/// Normalise histograms etc., after the run
void finalize() {
  const double expected = 36.1 * crossSection() / femtobarn;
  normalize(_h_sigmaM, expected / sumOfWeights());
  normalize(_h_modeta, expected / sumOfWeights());
  // _flows.scale(99.7/numEvents());
  // @todo suppress output in reentrant mode?
  MSG_INFO(_flows);
}

/// @}

private:

/// @name Histograms
Histo1DPtr _h_sigmaM, _h_modeta;

// Cutflows
CutflowsPtr _flows;

};

RIVET_DECLARE_PLUGIN(ATLAS_2018_I1667046);

} ```