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ATLAS_2016_CONF_2016_054

ATLAS 2016 1-lepton SUSY search at 13 \text{TeV}, from 14.8/fb CONF note
Experiment: ATLAS (LHC)
Status: UNVALIDATED
Authors:
  • Andy Buckley
No references listed
Beams: p+ p+
Beam energies: (6500.0, 6500.0) GeV
Run details:
  • BSM signal events

A search for squarks and gluinos in final states with an isolated electron or muon, multiple jets and large missing transverse momentum using proton--proton collision data at a centre-of-mass energy of $\sqrt{s} = 13 \text{TeV}$. The dataset corresponds to an integrated luminosity of 14.8/fb, recorded in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider.

Source code: ATLAS_2016_CONF_2016_054.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/PromptFinalState.hh"
  5#include "Rivet/Projections/FastJets.hh"
  6#include "Rivet/Projections/Sphericity.hh"
  7#include "Rivet/Projections/SmearedParticles.hh"
  8#include "Rivet/Projections/SmearedJets.hh"
  9#include "Rivet/Projections/SmearedMET.hh"
 10
 11namespace Rivet {
 12
 13
 14  /// @brief ATLAS 2016 1-lepton SUSY search, from 14.8/fb CONF note
 15  class ATLAS_2016_CONF_2016_054 : public Analysis {
 16  public:
 17
 18    /// Constructor
 19    RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2016_CONF_2016_054);
 20
 21
 22    /// @name Analysis methods
 23    /// @{
 24
 25    /// Book histograms and initialise projections before the run
 26    void init() {
 27
 28      // Initialise and register projections
 29      FinalState calofs(Cuts::abseta < 4.9);
 30      FastJets fj(calofs, JetAlg::ANTIKT, 0.4);
 31      declare(fj, "TruthJets");
 32      declare(SmearedJets(fj, JET_SMEAR_ATLAS_RUN2, [](const Jet& j) {
 33            if (j.abseta() > 2.5) return 0.;
 34            return j.bTagged(Cuts::pT > 5*GeV) ? 0.77 :
 35              j.cTagged(Cuts::pT > 5*GeV) ? 1/6.2 : 1/134.; }), "Jets");
 36
 37      MissingMomentum mm(calofs);
 38      declare(mm, "TruthMET");
 39      declare(SmearedMET(mm, MET_SMEAR_ATLAS_RUN2), "MET");
 40
 41      FinalState es(Cuts::abseta < 2.47 && Cuts::pT > 7*GeV && Cuts::abspid == PID::ELECTRON);
 42      declare(es, "TruthElectrons");
 43      declare(SmearedParticles(es, ELECTRON_RECOEFF_ATLAS_RUN2, ELECTRON_SMEAR_ATLAS_RUN2), "Electrons");
 44
 45      FinalState mus(Cuts::abseta < 2.5 && Cuts::pT > 6*GeV && Cuts::abspid == PID::MUON);
 46      declare(mus, "TruthMuons");
 47      declare(SmearedParticles(mus, MUON_EFF_ATLAS_RUN2, MUON_SMEAR_ATLAS_RUN2), "Muons");
 48
 49
 50      // Book histograms/counters
 51      book(_h_gg2j,"GG-2j");
 52      book(_h_gg6j0,"GG-6j-0bulk");
 53      book(_h_gg6j1,"GG-6j-1highmass");
 54      book(_h_gg4j0,"GG-4j-0lowx");
 55      book(_h_gg4j1,"GG-4j-1lowxbveto");
 56      book(_h_gg4j2,"GG-4j-2highx");
 57      book(_h_ss4j0,"SS-4j-0x12");
 58      book(_h_ss4j1,"SS-4j-1lowx");
 59      book(_h_ss5j0,"SS-5j-0x12");
 60      book(_h_ss5j1,"SS-5j-1highx");
 61
 62    }
 63
 64
 65    /// Perform the per-event analysis
 66    void analyze(const Event& event) {
 67
 68      // Get baseline electrons, muons, and jets
 69      Particles elecs = apply<ParticleFinder>(event, "Electrons").particles();
 70      Particles muons = apply<ParticleFinder>(event, "Muons").particles();
 71      Jets jets = apply<JetFinder>(event, "Jets").jetsByPt(Cuts::pT > 20*GeV && Cuts::abseta < 4.5);
 72
 73      // Jet/electron/muons overlap removal and selection
 74      // Remove any jet within dR = 0.2 of an electron
 75      for (const Particle& e : elecs)
 76        idiscard(jets, deltaRLess(e, 0.2, RAPIDITY));
 77      // Remove any electron within dR = 0.01 of a muon
 78      for (const Particle& m : muons)
 79        idiscard(elecs, deltaRLess(m, 0.01, RAPIDITY));
 80      // Assemble b-jets collection, and remove muons within dR = 0.2 of a b-tagged jet
 81      Jets bjets;
 82      for (const Jet& j : jets) {
 83        if (j.abseta() < 2.5 && j.pT() > 30*GeV && j.bTagged(Cuts::pT > 5*GeV)) {
 84          bjets += j;
 85          idiscard(muons, deltaRLess(j, 0.2, RAPIDITY));
 86        }
 87      }
 88      // Remove any jet within dR = 0.2 of a muon if track conditions are met
 89      for (const Particle& m : muons)
 90        idiscard(jets, [&](const Jet& j){
 91            if (deltaR(j,m) > 0.2) return false;
 92            /// @todo Add track efficiency random filtering
 93            const Particles trks = j.particles(Cuts::abscharge > 0 && Cuts::pT > 0.5*GeV);
 94            return trks.size() < 4 || m.pT()/j.pT() > 0.7;
 95          });
 96      // Remove any muon within dR = 0.2 of a remaining jet if the same track conditions are *not* met
 97      /// @todo There must be nicer way to do complementary removal...
 98      for (const Jet& j : jets) {
 99        /// @todo Add track efficiency random filtering
100        const size_t ntrks = j.particles(Cuts::abscharge > 0 && Cuts::pT > 0.5*GeV).size();
101        idiscard(muons, [&](const Particle& m){
102            if (deltaR(j,m) > 0.2) return false;
103            return ntrks > 3 && m.pT()/j.pT() < 0.7;
104          });
105      }
106      // Remove any muon with dR close to a remaining jet, via a functional form
107      for (const Jet& j : jets)
108        idiscard(muons, [&](const Particle& m) { return deltaR(m,j, RAPIDITY) < min(0.4, 0.04 + 10*GeV/m.pT()); });
109
110
111      // Signal jet selection
112      const Jets sigjets = select(jets, Cuts::pT > 30*GeV && Cuts::abseta < 2.8);
113      const Jets sigbjets = bjets;
114
115      // "Gradient-loose" signal lepton selection
116      const ParticleEffFilter grad_loose_filter([](const Particle& e) { return e.pT() > 60*GeV ? 0.98 : 0.95; });
117      Particles sigelecs = select(elecs, grad_loose_filter);
118      Particles sigmuons = select(muons, grad_loose_filter);
119      // Tight electron selection (NB. assuming independent eff to gradient-loose... hmm)
120      iselect(sigelecs, ParticleEffFilter(ELECTRON_EFF_ATLAS_RUN2_TIGHT));
121
122
123      // MET calculation (NB. done generically, with smearing, rather than via explicit physics objects)
124      const Vector3 vmet = -apply<SmearedMET>(event, "MET").vectorEt();
125      const double etmiss = vmet.mod();
126
127
128      //////////////////
129
130
131      // Event selection cuts
132      if (sigelecs.size() + sigmuons.size() != 1) vetoEvent;
133      const Particle siglepton = sigelecs.empty() ? sigmuons.front() : sigelecs.front();
134
135      // mT and m_eff
136      const double mT = sqrt(2*siglepton.pT()*etmiss*(1-cos(deltaPhi(siglepton,vmet))));
137      const double meff = siglepton.pT() + sum(sigjets, pT, 0.0) + etmiss;
138
139      // Aplanarities
140      Sphericity sph;
141      vector<FourMomentum> vecs;
142      transform(sigjets, vecs, mom);
143      sph.calc(vecs);
144      const double jet_aplanarity = sph.aplanarity();
145      vecs += siglepton.mom();
146      sph.calc(vecs);
147      const double lepton_aplanarity = sph.aplanarity();
148
149
150      //////////////////
151
152
153      // Fill counters
154      // GG
155      if (siglepton.pT() < 35*GeV && sigjets.size() >= 2 &&
156          sigjets[0].pT() > 200*GeV && sigjets[1].pT() > 30*GeV &&
157          mT > 100*GeV && etmiss > 460*GeV && etmiss/meff > 0.35) _h_gg2j->fill();
158      if (siglepton.pT() > 35*GeV && sigjets.size() >= 6 &&
159          sigjets[0].pT() > 125*GeV && sigjets[5].pT() > 30*GeV &&
160          mT > 225*GeV && etmiss > 250*GeV && meff > 1000*GeV && etmiss/meff > 0.2 &&
161          jet_aplanarity > 0.04) _h_gg6j0->fill();
162      if (siglepton.pT() > 35*GeV && sigjets.size() >= 6 &&
163          sigjets[0].pT() > 125*GeV && sigjets[5].pT() > 30*GeV &&
164          mT > 225*GeV && etmiss > 250*GeV && meff > 2000*GeV && etmiss/meff > 0.1 &&
165          jet_aplanarity > 0.04) _h_gg6j1->fill();
166      if (sigjets.size() >= 4 && sigjets[3].pT() > 100*GeV &&
167          mT > 125*GeV && etmiss > 250*GeV && meff > 2000*GeV && jet_aplanarity > 0.06) _h_gg4j0->fill();
168      if (sigjets.size() >= 4 && sigjets[3].pT() > 100*GeV && sigbjets.empty() &&
169          mT > 125*GeV && etmiss > 250*GeV && meff > 2000*GeV && jet_aplanarity > 0.03) _h_gg4j1->fill();
170      if (siglepton.pT() > 35*GeV &&
171          sigjets.size() >= 4 && sigjets[0].pT() > 400*GeV && inRange(sigjets[3].pT(), 30*GeV, 100*GeV) &&
172          mT > 475*GeV && etmiss > 250*GeV && meff > 1600*GeV && etmiss/meff > 0.3) _h_gg4j2->fill();
173      // SS
174      if (siglepton.pT() > 35*GeV && sigjets.size() >= 4 && sigjets[3].pT() > 50*GeV &&
175          mT > 175*GeV && etmiss > 300*GeV && meff > 1200*GeV && lepton_aplanarity > 0.08) _h_ss4j0->fill();
176      if (siglepton.pT() > 35*GeV && sigjets.size() >= 5 && sigjets[4].pT() > 50*GeV && sigbjets.empty() &&
177          mT > 175*GeV && etmiss > 300*GeV && etmiss/meff > 0.2) _h_ss5j0->fill();
178      if (siglepton.pT() > 35*GeV && sigjets.size() >= 4 && sigjets[0].pT() > 250*GeV && sigjets[3].pT() > 30*GeV &&
179          inRange(mT, 150*GeV, 400*GeV) && etmiss > 250*GeV && lepton_aplanarity > 0.03) _h_ss4j1->fill();
180      if (siglepton.pT() > 35*GeV && sigjets.size() >= 5 && sigjets[4].pT() > 30*GeV &&
181          mT > 400*GeV && etmiss > 400*GeV && lepton_aplanarity > 0.03) _h_ss5j1->fill();
182
183    }
184
185
186    /// Normalise counters after the run
187    void finalize() {
188
189      const double sf = 14.8*crossSection()/femtobarn/sumOfWeights();
190      scale(_h_gg2j, sf); scale(_h_gg6j0, sf); scale(_h_gg6j1, sf);
191      scale(_h_gg4j0, sf); scale(_h_gg4j1, sf); scale(_h_gg4j2, sf);
192      scale(_h_ss4j0, sf); scale(_h_ss4j1, sf); scale(_h_ss5j0, sf);
193      scale(_h_ss5j1, sf);
194
195    }
196
197    /// @}
198
199
200  private:
201
202    /// @name Histograms
203    /// @{
204    CounterPtr _h_gg2j, _h_gg6j0, _h_gg6j1, _h_gg4j0, _h_gg4j1, _h_gg4j2;
205    CounterPtr _h_ss4j0, _h_ss4j1, _h_ss5j0,_h_ss5j1;
206    /// @}
207
208
209  };
210
211
212
213  RIVET_DECLARE_PLUGIN(ATLAS_2016_CONF_2016_054);
214
215
216}