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ATLAS_2011_S9225137

High-jet-multiplicity squark and gluino search
Experiment: ATLAS (LHC)
Inspire ID: 939504
Status: VALIDATED
Authors:
  • Peter Richardson
References: 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 1.34 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_2011_S9225137.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/ChargedFinalState.hh"
  5#include "Rivet/Projections/VisibleFinalState.hh"
  6#include "Rivet/Projections/VetoedFinalState.hh"
  7#include "Rivet/Projections/IdentifiedFinalState.hh"
  8#include "Rivet/Projections/FastJets.hh"
  9#include "Rivet/Tools/RivetMT2.hh"
 10
 11namespace Rivet {
 12
 13
 14  /// High-jet-multiplicity squark and gluino search
 15  class ATLAS_2011_S9225137 : public Analysis {
 16  public:
 17
 18    /// Constructor
 19    RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2011_S9225137);
 20
 21
 22    /// @name Analysis methods
 23    //@{
 24
 25    /// Book histograms and initialise projections before the run
 26    void init() {
 27
 28      // veto region electrons
 29      Cut vetocut = Cuts::absetaIn(1.37, 1.52);
 30      IdentifiedFinalState veto_elecs(vetocut && Cuts::pT > 10*GeV);
 31      veto_elecs.acceptIdPair(PID::ELECTRON);
 32      declare(veto_elecs, "veto_elecs");
 33
 34      // projection to find the electrons
 35      IdentifiedFinalState elecs(Cuts::abseta < 2.47 && Cuts::pT > 20*GeV);
 36      elecs.acceptIdPair(PID::ELECTRON);
 37      declare(elecs, "elecs");
 38
 39      // projection to find the muons
 40      IdentifiedFinalState muons(Cuts::abseta < 2.4 && Cuts::pT > 10*GeV);
 41      muons.acceptIdPair(PID::MUON);
 42      declare(muons, "muons");
 43
 44      // for pTmiss
 45      declare(VisibleFinalState(Cuts::abseta < 4.9), "vfs");
 46
 47      VetoedFinalState vfs;
 48      vfs.addVetoPairId(PID::MUON);
 49
 50      /// Jet finder
 51      declare(FastJets(vfs, FastJets::ANTIKT, 0.4), "AntiKtJets04");
 52
 53      // all tracks (to do deltaR with leptons)
 54      declare(ChargedFinalState(Cuts::abseta < 3), "cfs");
 55
 56      /// Book histograms
 57      book(_etmisspT_55_NJ_6_obs , 1,1,1);
 58      book(_etmisspT_55_NJ_6_bac , 1,1,2);
 59      book(_etmisspT_55_NJ_6_sig , 1,1,3);
 60      book(_etmisspT_55_NJ_7_obs ,13,1,1);
 61      book(_etmisspT_55_NJ_7_bac ,13,1,2);
 62      book(_etmisspT_55_NJ_7_sig ,13,1,3);
 63      book(_etmisspT_55_NJ_8_obs ,15,1,1);
 64      book(_etmisspT_55_NJ_8_bac ,15,1,2);
 65      book(_etmisspT_55_NJ_8_sig ,15,1,3);
 66      book(_etmisspT_80_NJ_5_obs , 2,1,1);
 67      book(_etmisspT_80_NJ_5_bac , 2,1,2);
 68      book(_etmisspT_80_NJ_5_sig , 2,1,3);
 69      book(_etmisspT_80_NJ_6_obs ,14,1,1);
 70      book(_etmisspT_80_NJ_6_bac ,14,1,2);
 71      book(_etmisspT_80_NJ_6_sig ,14,1,3);
 72      book(_etmisspT_80_NJ_7_obs ,16,1,1);
 73      book(_etmisspT_80_NJ_7_bac ,16,1,2);
 74      book(_etmisspT_80_NJ_7_sig ,16,1,3);
 75
 76      book(_njet55A_obs , 3,1,1);
 77      book(_njet55A_bac , 3,1,2);
 78      book(_njet55A_sig , 3,1,3);
 79      book(_njet55B_obs , 4,1,1);
 80      book(_njet55B_bac , 4,1,2);
 81      book(_njet55B_sig , 4,1,3);
 82      book(_njet55C_obs ,17,1,1);
 83      book(_njet55C_bac ,17,1,2);
 84      book(_njet55C_sig ,17,1,3);
 85      book(_njet80A_obs , 5,1,1);
 86      book(_njet80A_bac , 5,1,2);
 87      book(_njet80A_sig , 5,1,3);
 88      book(_njet80B_obs , 6,1,1);
 89      book(_njet80B_bac , 6,1,2);
 90      book(_njet80B_sig , 6,1,3);
 91      book(_njet80C_obs ,18,1,1);
 92      book(_njet80C_bac ,18,1,2);
 93      book(_njet80C_sig ,18,1,3);
 94
 95      book(_count_7j55 ,"count_7j55", 1, 0., 1.);
 96      book(_count_8j55 ,"count_8j55", 1, 0., 1.);
 97      book(_count_6j80 ,"count_6j80", 1, 0., 1.);
 98      book(_count_7j80 ,"count_7j80", 1, 0., 1.);
 99
100    }
101
102
103    /// Perform the per-event analysis
104    void analyze(const Event& event) {
105      const double weight = 1.0;
106      // apply electron veto region
107      Particles veto_e
108        = apply<IdentifiedFinalState>(event, "veto_elecs").particles();
109      if ( ! veto_e.empty() ) {
110        MSG_DEBUG("electrons in veto region");
111        vetoEvent;
112      }
113
114      // get the jet candidates
115      Jets cand_jets;
116      for (const Jet& jet :
117               apply<FastJets>(event, "AntiKtJets04").jetsByPt(20.0*GeV) ) {
118        if ( fabs( jet.eta() ) < 4.9 ) {
119          cand_jets.push_back(jet);
120        }
121      }
122
123      // candidate muons
124      Particles cand_mu;
125      Particles chg_tracks =
126        apply<ChargedFinalState>(event, "cfs").particles();
127      for ( const Particle & mu :
128                apply<IdentifiedFinalState>(event, "muons").particlesByPt() ) {
129        double pTinCone = -mu.pT();
130        for ( const Particle & track : chg_tracks ) {
131          if ( deltaR(mu.momentum(),track.momentum()) <= 0.2 )
132            pTinCone += track.pT();
133        }
134        if ( pTinCone < 1.8*GeV )
135          cand_mu.push_back(mu);
136      }
137
138      // candidate electrons
139
140      Particles cand_e  =
141        apply<IdentifiedFinalState>(event, "elecs").particlesByPt();
142
143      // resolve jet/lepton ambiguity
144      Jets cand_jets_2;
145      for ( const Jet& jet : cand_jets ) {
146        // candidates above eta=2.8 are jets
147        if ( fabs( jet.eta() ) >= 2.8 )
148          cand_jets_2.push_back( jet );
149        // otherwise more the R=0.2 from an electrons
150        else {
151          bool away_from_e = true;
152          for ( const Particle & e : cand_e ) {
153            if ( deltaR(e.momentum(),jet.momentum()) <= 0.2 ) {
154              away_from_e = false;
155              break;
156            }
157          }
158          if ( away_from_e )
159            cand_jets_2.push_back( jet );
160        }
161      }
162
163      // only keep electrons more than R=0.4 from jets
164      Particles recon_e;
165      for ( const Particle & e : cand_e ) {
166        bool away = true;
167        for ( const Jet& jet : cand_jets_2 ) {
168          if ( deltaR(e.momentum(),jet.momentum()) < 0.4 ) {
169            away = false;
170            break;
171          }
172        }
173        if ( away )
174          recon_e.push_back( e );
175      }
176
177      // only keep muons more than R=0.4 from jets
178      Particles recon_mu;
179      for ( const Particle & mu : cand_mu ) {
180        bool away = true;
181        for ( const Jet& jet : cand_jets_2 ) {
182          if ( deltaR(mu.momentum(),jet.momentum()) < 0.4 ) {
183            away = false;
184            break;
185          }
186        }
187        if ( away ) recon_mu.push_back( mu );
188      }
189
190      // pTmiss
191      Particles vfs_particles =
192        apply<VisibleFinalState>(event, "vfs").particles();
193      FourMomentum pTmiss;
194      for ( const Particle & p : vfs_particles ) {
195        pTmiss -= p.momentum();
196      }
197      double eTmiss = pTmiss.pT();
198
199      // final jet filter
200      Jets recon_jets;
201      for (const Jet& jet : cand_jets_2) {
202        if (jet.abseta() <= 2.8 ) recon_jets.push_back( jet );
203      }
204
205      // now only use recon_jets, recon_mu, recon_e
206
207      // reject events with electrons and muons
208      if ( ! ( recon_mu.empty() && recon_e.empty() ) ) {
209        MSG_DEBUG("Charged leptons left after selection");
210        vetoEvent;
211      }
212
213      // calculate H_T
214      double HT = 0;
215      for (const Jet& jet : recon_jets) {
216        if (jet.pT() > 40*GeV) HT += jet.pT() ;
217      }
218
219      // number of jets and deltaR
220      bool pass55DeltaR=true, pass80DeltaR=true;
221      size_t njet55=0, njet80=0;
222      for (size_t ix=0; ix < recon_jets.size(); ++ix) {
223        if (recon_jets[ix].pT() > 80*GeV) ++njet80;
224        if (recon_jets[ix].pT() > 55*GeV) ++njet55;
225        for (size_t iy = ix + 1; iy < recon_jets.size(); ++iy) {
226          if (recon_jets[ix].pT() > 55*GeV &&
227              recon_jets[iy].pT() > 55*GeV &&
228              deltaR(recon_jets[ix], recon_jets[iy]) < 0.6)
229            pass55DeltaR = false;
230          // if (recon_jets[ix].pT() > 80*GeV &&
231          //     recon_jets[iy].pT() > 80*GeV &&
232          //     deltaR(recon_jets[ix], recon_jets[iy]) < 0.6)
233          //   pass80DeltaR = false;
234        }
235      }
236
237      // require at least four jets with et > 55
238      if (njet55 <= 3) vetoEvent;
239
240      // plots of etmiss/ht
241      double etht = eTmiss/sqrt(HT);
242      if (njet55 == 6) {
243        _etmisspT_55_NJ_6_obs->fill(etht,weight);
244        _etmisspT_55_NJ_6_bac->fill(etht,weight);
245        _etmisspT_55_NJ_6_sig->fill(etht,weight);
246      } else if (njet55 == 7) {
247        _etmisspT_55_NJ_7_obs->fill(etht,weight);
248        _etmisspT_55_NJ_7_bac->fill(etht,weight);
249        _etmisspT_55_NJ_7_sig->fill(etht,weight);
250      } else if (njet55 == 8) {
251        _etmisspT_55_NJ_8_obs->fill(etht,weight);
252        _etmisspT_55_NJ_8_bac->fill(etht,weight);
253        _etmisspT_55_NJ_8_sig->fill(etht,weight);
254      }
255      if (njet80 == 5) {
256        _etmisspT_80_NJ_5_obs->fill(etht,weight);
257        _etmisspT_80_NJ_5_bac->fill(etht,weight);
258        _etmisspT_80_NJ_5_sig->fill(etht,weight);
259      } else if (njet80 == 6) {
260        _etmisspT_80_NJ_6_obs->fill(etht,weight);
261        _etmisspT_80_NJ_6_bac->fill(etht,weight);
262        _etmisspT_80_NJ_6_sig->fill(etht,weight);
263      } else if (njet80 == 7) {
264        _etmisspT_80_NJ_7_obs->fill(etht,weight);
265        _etmisspT_80_NJ_7_bac->fill(etht,weight);
266        _etmisspT_80_NJ_7_sig->fill(etht,weight);
267      }
268
269      if (etht > 1.5 && etht < 2.) {
270        if (njet55 > 3) {
271          _njet55A_obs->fill(njet55,weight);
272          _njet55A_bac->fill(njet55,weight);
273          _njet55A_sig->fill(njet55,weight);
274        }
275        if (njet80 > 3) {
276          _njet80A_obs->fill(njet80,weight);
277          _njet80A_bac->fill(njet80,weight);
278          _njet80A_sig->fill(njet80,weight);
279        }
280      } else if (etht > 2. && etht < 3.) {
281        if (njet55 > 3) {
282          _njet55B_obs->fill(njet55,weight);
283          _njet55B_bac->fill(njet55,weight);
284          _njet55B_sig->fill(njet55,weight);
285        }
286        if (njet80 > 3) {
287          _njet80B_obs->fill(njet80,weight);
288          _njet80B_bac->fill(njet80,weight);
289          _njet80B_sig->fill(njet80,weight);
290        }
291      } else {
292        if (njet55 > 3) {
293          _njet55C_obs->fill(njet55,weight);
294          _njet55C_bac->fill(njet55,weight);
295          _njet55C_sig->fill(njet55,weight);
296        }
297        if (njet80 > 3) {
298          _njet80C_obs->fill(njet80,weight);
299          _njet80C_bac->fill(njet80,weight);
300          _njet80C_sig->fill(njet80,weight);
301        }
302      }
303
304      // apply E_T/sqrt(H_T) cut
305      if (etht <= 3.5*GeV) {
306        MSG_DEBUG("Fails ET/sqrt(HT) cut ");
307        vetoEvent;
308      }
309
310      // check passes at least one delta5/ njet number cut
311      if (!(pass55DeltaR && njet55 >= 7) && !(pass80DeltaR && njet80 >= 6) ) {
312        MSG_DEBUG("Fails DeltaR cut or jet number cuts");
313        vetoEvent;
314      }
315
316      // 7j55
317      if (njet55 >= 7 && pass55DeltaR) _count_7j55->fill( 0.5, weight);
318      // 8j55
319      if (njet55 >= 8 && pass55DeltaR) _count_8j55->fill( 0.5, weight);
320      // 6j80
321      if (njet80 >= 6 && pass80DeltaR) _count_6j80->fill( 0.5, weight);
322      // 7j80
323      if (njet80 >= 7 && pass80DeltaR) _count_7j80->fill( 0.5, weight);
324    }
325
326    //@}
327
328    void finalize() {
329      const double norm = crossSection()/femtobarn*1.34/sumOfWeights();
330      scale(_etmisspT_55_NJ_6_obs,norm);
331      scale(_etmisspT_55_NJ_6_bac,norm);
332      scale(_etmisspT_55_NJ_6_sig,norm);
333      scale(_etmisspT_55_NJ_7_obs,norm);
334      scale(_etmisspT_55_NJ_7_bac,norm);
335      scale(_etmisspT_55_NJ_7_sig,norm);
336      scale(_etmisspT_55_NJ_8_obs,norm);
337      scale(_etmisspT_55_NJ_8_bac,norm);
338      scale(_etmisspT_55_NJ_8_sig,norm);
339      scale(_etmisspT_80_NJ_5_obs,norm);
340      scale(_etmisspT_80_NJ_5_bac,norm);
341      scale(_etmisspT_80_NJ_5_sig,norm);
342      scale(_etmisspT_80_NJ_6_obs,norm);
343      scale(_etmisspT_80_NJ_6_bac,norm);
344      scale(_etmisspT_80_NJ_6_sig,norm);
345      scale(_etmisspT_80_NJ_7_obs,norm);
346      scale(_etmisspT_80_NJ_7_bac,norm);
347      scale(_etmisspT_80_NJ_7_sig,norm);
348      scale(_njet55A_obs,norm);
349      scale(_njet55A_bac,norm);
350      scale(_njet55A_sig,norm);
351      scale(_njet55B_obs,norm);
352      scale(_njet55B_bac,norm);
353      scale(_njet55B_sig,norm);
354      scale(_njet55C_obs,norm);
355      scale(_njet55C_bac,norm);
356      scale(_njet55C_sig,norm);
357      scale(_njet80A_obs,norm);
358      scale(_njet80A_bac,norm);
359      scale(_njet80A_sig,norm);
360      scale(_njet80B_obs,norm);
361      scale(_njet80B_bac,norm);
362      scale(_njet80B_sig,norm);
363      scale(_njet80C_obs,norm);
364      scale(_njet80C_bac,norm);
365      scale(_njet80C_sig,norm);
366      scale(_count_7j55,norm);
367      scale(_count_8j55,norm);
368      scale(_count_6j80,norm);
369      scale(_count_7j80,norm);
370    }
371
372  private:
373
374    /// @name Histograms
375    //@{
376    Histo1DPtr _etmisspT_55_NJ_6_obs;
377    Histo1DPtr _etmisspT_55_NJ_6_bac;
378    Histo1DPtr _etmisspT_55_NJ_6_sig;
379    Histo1DPtr _etmisspT_55_NJ_7_obs;
380    Histo1DPtr _etmisspT_55_NJ_7_bac;
381    Histo1DPtr _etmisspT_55_NJ_7_sig;
382    Histo1DPtr _etmisspT_55_NJ_8_obs;
383    Histo1DPtr _etmisspT_55_NJ_8_bac;
384    Histo1DPtr _etmisspT_55_NJ_8_sig;
385    Histo1DPtr _etmisspT_80_NJ_5_obs;
386    Histo1DPtr _etmisspT_80_NJ_5_bac;
387    Histo1DPtr _etmisspT_80_NJ_5_sig;
388    Histo1DPtr _etmisspT_80_NJ_6_obs;
389    Histo1DPtr _etmisspT_80_NJ_6_bac;
390    Histo1DPtr _etmisspT_80_NJ_6_sig;
391    Histo1DPtr _etmisspT_80_NJ_7_obs;
392    Histo1DPtr _etmisspT_80_NJ_7_bac;
393    Histo1DPtr _etmisspT_80_NJ_7_sig;
394    Histo1DPtr _njet55A_obs;
395    Histo1DPtr _njet55A_bac;
396    Histo1DPtr _njet55A_sig;
397    Histo1DPtr _njet55B_obs;
398    Histo1DPtr _njet55B_bac;
399    Histo1DPtr _njet55B_sig;
400    Histo1DPtr _njet55C_obs;
401    Histo1DPtr _njet55C_bac;
402    Histo1DPtr _njet55C_sig;
403    Histo1DPtr _njet80A_obs;
404    Histo1DPtr _njet80A_bac;
405    Histo1DPtr _njet80A_sig;
406    Histo1DPtr _njet80B_obs;
407    Histo1DPtr _njet80B_bac;
408    Histo1DPtr _njet80B_sig;
409    Histo1DPtr _njet80C_obs;
410    Histo1DPtr _njet80C_bac;
411    Histo1DPtr _njet80C_sig;
412    Histo1DPtr _count_7j55;
413    Histo1DPtr _count_8j55;
414    Histo1DPtr _count_6j80;
415    Histo1DPtr _count_7j80;
416    //@}
417
418  };
419
420
421
422  RIVET_DECLARE_ALIASED_PLUGIN(ATLAS_2011_S9225137, ATLAS_2011_I939504);
423
424}