Rivet analyses referenceATLAS_2012_CONF_2012_104Search for supersymmetry at 8 TeV with jets, missing transverse momentum and one leptonExperiment: ATLAS (LHC) Status: OBSOLETE Authors:
Beam energies: (4000.0, 4000.0) GeV Run details:
One lepton search for supersymmmetric particles by ATLAS at 8 TeV with $5.8\,\text{fb}^{-1}$ integrated luminosity. Event counts in the signal regions are implemented as one-bin histograms. Histograms for effective mass are implemented for the two signal hard lepton signal regions and the ratio of missing transverse energy to effective mass for the soft lepton region. Source code: ATLAS_2012_CONF_2012_104.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/IdentifiedFinalState.hh"
7#include "Rivet/Projections/VetoedFinalState.hh"
8#include "Rivet/Projections/FastJets.hh"
9
10namespace Rivet {
11
12
13 class ATLAS_2012_CONF_2012_104 : public Analysis {
14 public:
15
16 /// Constructor
17 ATLAS_2012_CONF_2012_104()
18 : Analysis("ATLAS_2012_CONF_2012_104")
19 { }
20
21
22 /// @name Analysis methods
23 /// @{
24
25 /// Book histograms and initialize projections before the run
26 void init() {
27
28 // projection to find the electrons
29 IdentifiedFinalState elecs(Cuts::abseta < 2.47 && Cuts::pT > 10*GeV);
30 elecs.acceptIdPair(PID::ELECTRON);
31 declare(elecs, "elecs");
32
33 // projection to find the muons
34 IdentifiedFinalState muons(Cuts::abseta < 2.4 && Cuts::pT > 10*GeV);
35 muons.acceptIdPair(PID::MUON);
36 declare(muons, "muons");
37
38 // Jet finder
39 VetoedFinalState vfs;
40 vfs.addVetoPairId(PID::MUON);
41 declare(FastJets(vfs, JetAlg::ANTIKT, 0.4), "AntiKtJets04");
42
43 // all tracks (to do deltaR with leptons)
44 declare(ChargedFinalState(Cuts::abseta < 3 && Cuts::pT > 0.5*GeV), "cfs");
45
46 // for pTmiss
47 declare(VisibleFinalState(Cuts::abseta < 4.9),"vfs");
48
49 // Book histograms
50 book(_count_e ,"count_e" , 1, 0., 1.);
51 book(_count_mu ,"count_mu", 1, 0., 1.);
52
53 book(_hist_eTmiss_e ,"hist_eTmiss_e" , 25, 0., 1000.);
54 book(_hist_eTmiss_mu ,"hist_eTmiss_mu" , 25, 0., 1000.);
55
56 }
57
58 /// Perform the per-event analysis
59 void analyze(const Event& event) {
60
61 // get the candiate jets
62 Jets cand_jets;
63 for ( const Jet& jet :
64 apply<FastJets>(event, "AntiKtJets04").jetsByPt(Cuts::pT > 20*GeV && Cuts::abseta < 2.8) ) {
65 cand_jets.push_back(jet);
66 }
67
68 // get the candidate "medium" leptons without isolation
69 Particles cand_e;
70 for( const Particle & e :
71 apply<IdentifiedFinalState>(event, "elecs").particlesByPt()) {
72 // remove any leptons within 0.4 of any candidate jets
73 bool e_near_jet = false;
74 for ( const Jet& jet : cand_jets ) {
75 double dR = deltaR(e.momentum(),jet.momentum());
76 if ( dR < 0.4 && dR > 0.2 ) {
77 e_near_jet = true;
78 break;
79 }
80 }
81 if ( ! e_near_jet ) cand_e.push_back(e);
82 }
83 Particles cand_mu;
84 for( const Particle & mu :
85 apply<IdentifiedFinalState>(event, "muons").particlesByPt()) {
86 // remove any leptons within 0.4 of any candidate jets
87 bool mu_near_jet = false;
88 for ( const Jet& jet : cand_jets ) {
89 if ( deltaR(mu.momentum(),jet.momentum()) < 0.4 ) {
90 mu_near_jet = true;
91 break;
92 }
93 }
94 if ( ! mu_near_jet ) cand_mu.push_back(mu);
95 }
96 // apply the isolation
97 Particles chg_tracks =
98 apply<ChargedFinalState>(event, "cfs").particles();
99 // pTcone around muon track (hard)
100 Particles recon_mu;
101 for ( const Particle & mu : cand_mu ) {
102 double pTinCone = -mu.pT();
103 if(-pTinCone<25.) continue;
104 for ( const Particle & track : chg_tracks ) {
105 if ( deltaR(mu.momentum(),track.momentum()) < 0.2 )
106 pTinCone += track.pT();
107 }
108 if ( pTinCone < 1.8*GeV ) recon_mu.push_back(mu);
109 }
110 // pTcone around electron track (hard)
111 Particles recon_e;
112 for ( const Particle & e : cand_e ) {
113 double pTinCone = -e.pT();
114 if(-pTinCone<25.) continue;
115 for ( const Particle & track : chg_tracks ) {
116 if ( deltaR(e.momentum(),track.momentum()) < 0.2 )
117 pTinCone += track.pT();
118 }
119 if ( pTinCone < 0.1 * e.pT() ) recon_e.push_back(e);
120 }
121
122 // discard jets that overlap with electrons
123 Jets recon_jets;
124 for ( const Jet& jet : cand_jets ) {
125 if(jet.abseta()>2.5||
126 jet.perp()<25.) continue;
127 bool away_from_e = true;
128 for ( const Particle & e : cand_e ) {
129 if ( deltaR(e.momentum(),jet.momentum()) < 0.2 ) {
130 away_from_e = false;
131 break;
132 }
133 }
134 if ( away_from_e ) recon_jets.push_back( jet );
135 }
136
137 // pTmiss
138 FourMomentum pTmiss;
139 for ( const Particle & p :
140 apply<VisibleFinalState>(event, "vfs").particles() ) {
141 pTmiss -= p.momentum();
142 }
143 double eTmiss = pTmiss.pT();
144
145 // at least 4 jets with pT>80.
146 if(recon_jets.size()<4 || recon_jets[3].perp()<80.) vetoEvent;
147
148 // only 1 signal lepton
149 if( recon_e.size() + recon_mu.size() != 1 )
150 vetoEvent;
151 if( cand_e .size() + cand_mu .size() != 1 )
152 vetoEvent;
153
154 // start of meff calculation
155 double HT=0.;
156 for( const Jet & jet : recon_jets) {
157 double pT = jet.perp();
158 if(pT>40.) HT += pT;
159 }
160
161 // get the lepton
162 Particle lepton = recon_e.empty() ? recon_mu[0] : recon_e[0];
163
164 // lepton variables
165 double pT = lepton.perp();
166
167 double mT = 2.*(pT*eTmiss -
168 lepton.px()*pTmiss.px() -
169 lepton.py()*pTmiss.py());
170 mT = sqrt(mT);
171 HT += pT;
172 double m_eff_inc = HT + eTmiss + pT;
173 double m_eff_4 = eTmiss + pT;
174 for(unsigned int ix=0;ix<4;++ix)
175 m_eff_4 += recon_jets[ix].perp();
176
177 // four jet selecton
178 if(mT>100.&& eTmiss/m_eff_4>0.2 &&
179 m_eff_inc > 800.) {
180 if( eTmiss > 250. ) {
181 if(lepton.abspid()==PID::ELECTRON)
182 _count_e->fill(0.5);
183 else if(lepton.abspid()==PID::MUON)
184 _count_mu->fill(0.5);
185 }
186 if(lepton.abspid()==PID::ELECTRON)
187 _hist_eTmiss_e ->fill(eTmiss);
188 else if(lepton.abspid()==PID::MUON)
189 _hist_eTmiss_mu->fill(eTmiss);
190 }
191 }
192 /// @}
193
194
195 void finalize() {
196
197 double norm = 5.8* crossSection()/sumOfWeights()/femtobarn;
198 scale(_count_e ,norm);
199 scale(_count_mu,norm);
200 scale(_hist_eTmiss_e ,40.*norm);
201 scale(_hist_eTmiss_mu ,40.*norm);
202
203 }
204
205 private:
206
207 /// @name Histograms
208 /// @{
209 Histo1DPtr _count_e ;
210 Histo1DPtr _count_mu;
211
212 Histo1DPtr _hist_eTmiss_e ;
213 Histo1DPtr _hist_eTmiss_mu;
214 /// @}
215
216 };
217
218 RIVET_DECLARE_PLUGIN(ATLAS_2012_CONF_2012_104);
219
220}
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