Rivet analyses referenceCMS_2016_I1454211Boosted $t\bar{t}$ in $pp$ collisions at $\sqrt{s} = 8 \text{TeV}$Experiment: CMS (LHC) Inspire ID: 1454211 Status: VALIDATED Authors:
Beam energies: (4000.0, 4000.0) GeV Run details:
The cross section for pair production of top quarks with high transverse momenta ($p_\mathrm{T} > 400$ \text{GeV}) is measured in 19.7 fb$^{-1}$ of $\mathrm{pp}$ collisions, collected with the CMS detector at $\sqrt{s} = 8 \text{TeV}$. The measurement is performed for lepton+jets events, where one top quark decays according to $t \rightarrow Wb \rightarrow \ell \nu b$, with $\ell$ denoting an electron or muon, and the second top quark decays to an hadronic final state and is reconstructed as a single large-radius jet and identified as a top quark candidate using jet substructure techniques. Integrated cross sections, as well as differential cross sections as a function of the top quark $p_\mathrm{T}$ and rapidity, are measured both at particle level within a fiducial region resembling the detector-level selections and at parton level. RIVET: This analysis is to be run on $t\bar{t}$ Monte Carlo. It utilizes the PartonicTops projection, which assumes top quarks in the event record. The analysis has been validated with Powheg+Pythia6. The parton-level phase space is defined by requiring two PartonicTops. Exactly one PartonicTop must decay directly to a muon or electron (no intermediate tau), and exactly one PartonicTop decays hadronically. For $t\bar{t}$ Monte Carlo, this is equivalent to requiring the event to be semileptonic at parton level. The parton-level top quark is defined as the hadronically decaying top. The parton-level top quark is required to have $p_\mathrm{T} > 400 \text{GeV}$. The particle-level phase space is defined using the following object definitions: - Lepton: A dressed electron or muon, meaning the lepton has been clustered with all photons within a cone of $R=0.1$. The DressedLepton projection is used to construct the dressed lepton. The lepton is required to have $p_\mathrm{T} > 45$ GeV and $|\eta| < 2.1$. - B Jet Candidate: Gen AK5 jets are formed by clustering the final state particles in the event using the anti-$k_{T}$ algorithm with distance parameter $R=0.5$. Neutrinos are excluded from the clustering, as are any particles included in the dressed lepton. The gen AK5 jet is required to have $p_{T} > 30$ GeV and $|\eta| < 2.4$. Gen AK5 jets in the same hemisphere as the lepton ($\Delta R(e/\mu, \mathrm{jet}) < \pi/2$) are defined as $b$-jet candidates. - Top Jet Candidate: Gen CA8 jets are formed by clustering the final state particles in the event using the Cambridge-Aachen algorithm with distance parameter $R=0.8$. Neutrinos are excluded from the clustering, as are any particles included in the dressed lepton. The gen CA8 jet is required to have $p_{T} > 30$ GeV and $|\eta| < 2.4$. Gen CA8 jets which have $p_{T} > 400$ GeV, 140 GeV $<$ mass $<$ 250 GeV, and are in the opposite hemisphere from the lepton ($\Delta{\rm R(e/\mu, jet)} > \pi/2$) are defined as top jet candidates. The particle-level phase space is defined by requiring $\geq 1$ b jet candidate, $\geq 1$ top jet candidate, and exactly one lepton. This is in addition to the parton-level semileptonic requirement. The highest-$p_\mathrm{T}$ top jet candidate is defined as the particle-level $t$ jet. Source code: CMS_2016_I1454211.cc 1#include "Rivet/Analysis.hh"
2#include "Rivet/Projections/FinalState.hh"
3#include "Rivet/Projections/FastJets.hh"
4#include "Rivet/Projections/PartonicTops.hh"
5#include "Rivet/Projections/DressedLeptons.hh"
6#include "Rivet/Projections/IdentifiedFinalState.hh"
7#include "Rivet/Projections/PromptFinalState.hh"
8#include "Rivet/Projections/VetoedFinalState.hh"
9#include "Rivet/Projections/InvMassFinalState.hh"
10#include "Rivet/Projections/MissingMomentum.hh"
11
12namespace Rivet {
13
14
15 /// Boosted ttbar in pp collisions at sqrtS = 8 TeV
16 /// @todo Use persistent weight counters
17 class CMS_2016_I1454211 : public Analysis {
18 public:
19
20 RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2016_I1454211);
21
22
23 // Set up projections and book histograms
24 void init() {
25
26 // Get options particle-level only.
27 _mode = 0;
28 if ( getOption("TMODE") == "PARTICLE" ) _mode = 0;
29 if ( getOption("TMODE") == "BOTH" ) _mode = 1;
30
31 // Complete final state
32 FinalState fs;
33
34 // Partonic tops
35 // Need these for flavour determination, even if only plotting particle-level
36 declare(PartonicTops(PartonicTops::DecayMode::ELECTRON, false), "ElectronPartonTops");
37 declare(PartonicTops(PartonicTops::DecayMode::MUON, false), "MuonPartonTops");
38 declare(PartonicTops(PartonicTops::DecayMode::HADRONIC), "HadronicPartonTops");
39
40 // Projection for electrons and muons
41 IdentifiedFinalState photons(fs, PID::PHOTON);
42
43 const Cut leptonCuts = Cuts::pt > 45*GeV && Cuts::abseta < 2.1;
44
45 IdentifiedFinalState el_id(fs, {{PID::ELECTRON, -PID::ELECTRON}});
46 PromptFinalState electrons(el_id);
47 DressedLeptons dressed_electrons(photons, electrons, 0.1, leptonCuts);
48 declare(dressed_electrons, "DressedElectrons");
49
50 IdentifiedFinalState mu_id(fs, {{PID::MUON, -PID::MUON}});
51 PromptFinalState muons(mu_id);
52 DressedLeptons dressed_muons(photons, muons, 0.1, leptonCuts);
53 declare(dressed_muons, "DressedMuons");
54
55 // Projection for jets
56 VetoedFinalState fs_jets(fs);
57 fs_jets.addVetoOnThisFinalState(dressed_muons);
58 fs_jets.addVetoOnThisFinalState(dressed_electrons);
59 fs_jets.vetoNeutrinos();
60 declare(FastJets(fs_jets, FastJets::ANTIKT, 0.5), "ak5jets");
61 declare(FastJets(fs_jets, FastJets::CAM, 0.8), "ca8jets");
62
63 if (_mode == 1) {
64 book(_hEl_topPt_parton , "d01-x01-y01"); // dsigma/dpt(top quark), el ch
65 book(_hEl_topY_parton , "d03-x01-y01"); // dsigma/dy(top quark), el ch
66 book(_hMu_topPt_parton , "d05-x01-y01"); // dsigma/dpt(top quark), mu ch
67 book(_hMu_topY_parton , "d07-x01-y01"); // dsigma/dy(top quark), mu ch
68 book(_hComb_topPt_parton , "d09-x01-y01"); // dsigma/dpt(top quark), comb ch
69 book(_hComb_topY_parton , "d11-x01-y01"); // dsigma/dy(top quark), comb ch
70
71 book(_hEl_topPt_parton_norm , "d13-x01-y01"); // 1/sigma dsigma/dpt(top quark), el ch
72 book(_hEl_topY_parton_norm , "d15-x01-y01"); // 1/sigma dsigma/dy(top quark), el ch
73 book(_hMu_topPt_parton_norm , "d17-x01-y01"); // 1/sigma dsigma/dpt(top quark), mu ch
74 book(_hMu_topY_parton_norm , "d19-x01-y01"); // 1/sigma dsigma/dy(top quark), mu ch
75 book(_hComb_topPt_parton_norm , "d21-x01-y01"); // 1/sigma dsigma/dpt(top quark), comb ch
76 book(_hComb_topY_parton_norm , "d23-x01-y01"); // 1/sigma dsigma/dy(top quark), comb ch
77 }
78
79 book(_hEl_topPt_particle , "d02-x01-y01"); // dsigma/dpt(top jet), el ch
80 book(_hEl_topY_particle , "d04-x01-y01"); // dsigma/dy(top jet), el ch
81 book(_hMu_topPt_particle , "d06-x01-y01"); // dsigma/dpt(top jet), mu ch
82 book(_hMu_topY_particle , "d08-x01-y01"); // dsigma/dy(top jet), mu ch
83 book(_hComb_topPt_particle , "d10-x01-y01"); // dsigma/dpt(top jet), comb ch
84 book(_hComb_topY_particle , "d12-x01-y01"); // dsigma/dy(top jet), comb ch
85 book(_hEl_topY_particle_norm , "d16-x01-y01"); // 1/sigma dsigma/dy(top jet), el ch
86 book(_hEl_topPt_particle_norm , "d14-x01-y01"); // 1/sigma dsigma/dpt(top jet), el ch
87 book(_hComb_topY_particle_norm , "d24-x01-y01"); // 1/sigma dsigma/dy(top jet), comb ch
88 book(_hMu_topPt_particle_norm , "d18-x01-y01"); // 1/sigma dsigma/dpt(top jet), mu ch
89 book(_hMu_topY_particle_norm , "d20-x01-y01"); // 1/sigma dsigma/dy(top jet), mu ch
90 book(_hComb_topPt_particle_norm , "d22-x01-y01"); // 1/sigma dsigma/dpt(top jet), comb ch
91
92 book(_hMu_cutflow , "mu_cutflow", 7, -0.5, 6.5);
93 book(_hEl_cutflow , "el_cutflow", 7, -0.5, 6.5);
94 }
95
96
97 // per event analysis
98 void analyze(const Event& event) {
99
100 // Total-events cutflow entries
101 _hMu_cutflow->fill(0.);
102 _hEl_cutflow->fill(0.);
103
104 // Do parton-level selection and channel determination
105 // Note that channel determination relies on partonic info, even for the particle-level tops
106 int partonCh = 0; //0 non-semi-lep, 1 muon, 2 electron
107 const Particles muonpartontops = apply<ParticleFinder>(event, "MuonPartonTops").particlesByPt();
108 const Particles electronpartontops = apply<ParticleFinder>(event, "ElectronPartonTops").particlesByPt();
109 if (electronpartontops.size() == 0 && muonpartontops.size() == 1) partonCh = 1;
110 else if (electronpartontops.size() == 1 && muonpartontops.size() == 0) partonCh = 2;
111 else vetoEvent;
112 const Particles hadronicpartontops = apply<ParticleFinder>(event, "HadronicPartonTops").particlesByPt();
113 if (hadronicpartontops.size() != 1) vetoEvent;
114
115 if (partonCh == 1) _hMu_cutflow->fill(1.); // muon at parton level
116 if (partonCh == 2) _hEl_cutflow->fill(1.); // electron at parton level
117
118 // Get hadronic parton-level top
119 const FourMomentum& partonTopP4 = hadronicpartontops.front();
120
121 // Do particle-level selection and channel determination
122 const DressedLeptons& dressed_electrons = apply<DressedLeptons>(event, "DressedElectrons");
123 const DressedLeptons& dressed_muons = apply<DressedLeptons>(event, "DressedMuons");
124
125 bool passParticleLep = false, passParticleTop = false;
126 FourMomentum lepton, particleTopP4;
127
128 if (partonCh == 1 && dressed_muons.dressedLeptons().size() == 1 && dressed_electrons.dressedLeptons().size() == 0) {
129 passParticleLep = true;
130 _hMu_cutflow->fill(3.); //muon at particle level
131 lepton = dressed_muons.dressedLeptons()[0].momentum();
132 }
133 if (partonCh == 2 && dressed_muons.dressedLeptons().size() == 0 && dressed_electrons.dressedLeptons().size() == 1) {
134 passParticleLep = true;
135 _hEl_cutflow->fill(3.); //electron at particle level
136 lepton = dressed_electrons.dressedLeptons()[0].momentum();
137 }
138
139 if (passParticleLep) {
140
141 // Jet cuts
142 Cut jetCuts = Cuts::pt > 30*GeV && Cuts::abseta < 2.4;
143 Jets genBjets, genTjets;
144 int nGenBjets = 0, nGenTjets = 0;
145
146 const FastJets& AK5jets = apply<FastJets>(event, "ak5jets");
147 for (const Jet& jet : AK5jets.jetsByPt(jetCuts)) {
148 if (deltaR(jet, lepton) > M_PI / 2.0) continue;
149 if (deltaR(jet, lepton) < 0.1) continue;
150 genBjets.push_back(jet);
151 nGenBjets += 1;
152 }
153
154 const FastJets& CA8jets = apply<FastJets>(event, "ca8jets");
155 for (const Jet& jet : CA8jets.jetsByPt(jetCuts)) {
156 if (deltaR(jet, lepton) < M_PI / 2.0) continue;
157 if (jet.mass() < 140*GeV) continue;
158 if (jet.mass() > 250*GeV) continue;
159 genTjets.push_back(jet);
160 nGenTjets += 1;
161 }
162
163 if (nGenBjets >=1) {
164 if (_mode == 1) {
165 if (partonCh == 1) _hMu_cutflow->fill(4.); // muon at parton level
166 if (partonCh == 2) _hEl_cutflow->fill(4.); // electron at parton level
167 }
168 if (nGenTjets >= 1) {
169 passParticleTop = true;
170 if (_mode == 1) {
171 if (partonCh == 1) _hMu_cutflow->fill(5.); // muon at parton level
172 if (partonCh == 2) _hEl_cutflow->fill(5.); // electron at parton level
173 }
174 particleTopP4 = genTjets[0];
175 }
176 }
177 }
178
179 const double weight = 1.0;
180 if (partonCh == 1) {
181 _nMu += weight;
182
183 if (_mode == 1) {
184 // protect against unphysical partons
185 if (partonTopP4.E() < 0) {
186 MSG_WARNING("Top parton with negative energy! Vetoing event. Try turning off partonic tops?");
187 vetoEvent;
188 }
189
190 _hMu_topPt_parton->fill(partonTopP4.pT()/GeV, weight);
191 _hMu_topPt_parton_norm->fill(partonTopP4.pT()/GeV, weight);
192 _hComb_topPt_parton->fill(partonTopP4.pT()/GeV, weight);
193 _hComb_topPt_parton_norm->fill(partonTopP4.pT()/GeV, weight);
194
195 if (partonTopP4.pT() >= 400*GeV) {
196 _nPassParton_mu += weight;
197 _hMu_cutflow->fill(2.);
198 _hMu_topY_parton->fill(partonTopP4.rapidity(), weight);
199 _hMu_topY_parton_norm->fill(partonTopP4.rapidity(), weight);
200 _hComb_topY_parton->fill(partonTopP4.rapidity(), weight);
201 _hComb_topY_parton_norm->fill(partonTopP4.rapidity(), weight);
202 }
203 }
204
205 if (passParticleTop) {
206 _hMu_topPt_particle->fill(particleTopP4.pT()/GeV, weight);
207 _hMu_topPt_particle_norm->fill(particleTopP4.pT()/GeV, weight);
208 _hComb_topPt_particle->fill(particleTopP4.pT()/GeV, weight);
209 _hComb_topPt_particle_norm->fill(particleTopP4.pT()/GeV, weight);
210
211 if (particleTopP4.pT() >= 400*GeV) {
212 _nPassParticle_mu += weight;
213 _hMu_cutflow->fill(6.);
214 _hMu_topY_particle->fill(particleTopP4.rapidity(), weight);
215 _hMu_topY_particle_norm->fill(particleTopP4.rapidity(), weight);
216 _hComb_topY_particle->fill(particleTopP4.rapidity(), weight);
217 _hComb_topY_particle_norm->fill(particleTopP4.rapidity(), weight);
218 }
219 }
220 }
221
222 if (partonCh == 2){
223 _nEl += weight;
224 if (_mode == 1) {
225 _hEl_topPt_parton->fill(partonTopP4.pT()/GeV, weight);
226 _hEl_topPt_parton_norm->fill(partonTopP4.pT()/GeV, weight);
227 _hComb_topPt_parton->fill(partonTopP4.pT()/GeV, weight);
228 _hComb_topPt_parton_norm->fill(partonTopP4.pT()/GeV, weight);
229
230 if (partonTopP4.pT() >= 400*GeV) {
231 _nPassParton_el += weight;
232 _hEl_cutflow->fill(2.);
233 _hEl_topY_parton->fill(partonTopP4.rapidity(), weight);
234 _hEl_topY_parton_norm->fill(partonTopP4.rapidity(), weight);
235 _hComb_topY_parton->fill(partonTopP4.rapidity(), weight);
236 _hComb_topY_parton_norm->fill(partonTopP4.rapidity(), weight);
237 }
238 }
239
240 if (passParticleTop) {
241 _hEl_topPt_particle->fill(particleTopP4.pT()/GeV, weight);
242 _hEl_topPt_particle_norm->fill(particleTopP4.pT()/GeV, weight);
243 _hComb_topPt_particle->fill(particleTopP4.pT()/GeV, weight);
244 _hComb_topPt_particle_norm->fill(particleTopP4.pT()/GeV, weight);
245
246 if (particleTopP4.pT() >= 400*GeV) {
247 _nPassParticle_el += weight;
248 _hEl_cutflow->fill(6.);
249 _hEl_topY_particle->fill(particleTopP4.rapidity(), weight);
250 _hEl_topY_particle_norm->fill(particleTopP4.rapidity(), weight);
251 _hComb_topY_particle->fill(particleTopP4.rapidity(), weight);
252 _hComb_topY_particle_norm->fill(particleTopP4.rapidity(), weight);
253 }
254 }
255 }
256 }
257
258 void finalize() {
259
260 normalize(_hMu_topPt_particle_norm); normalize(_hMu_topY_particle_norm); normalize(_hEl_topPt_particle_norm);
261 normalize(_hEl_topY_particle_norm); normalize(_hComb_topPt_particle_norm); normalize(_hComb_topY_particle_norm, 1.0, false);
262
263 const double sf = crossSection() / femtobarn / sumOfWeights();
264 scale(_hMu_topPt_particle, sf);
265 scale(_hEl_topPt_particle, sf);
266 scale(_hMu_topY_particle, sf);
267 scale(_hEl_topY_particle, sf);
268 scale(_hComb_topPt_particle, sf);
269 scale(_hComb_topY_particle, sf);
270
271 if (_mode == 1) {
272 normalize(_hMu_topPt_parton_norm); normalize(_hMu_topY_parton_norm); normalize(_hEl_topPt_parton_norm);
273 normalize(_hEl_topY_parton_norm); normalize(_hComb_topPt_parton_norm); normalize(_hComb_topY_parton_norm, 1.0, false);
274 scale(_hMu_topPt_parton, sf);
275 scale(_hEl_topPt_parton, sf);
276 scale(_hMu_topY_parton, sf);
277 scale(_hEl_topY_parton, sf);
278 scale(_hComb_topPt_parton, sf);
279 scale(_hComb_topY_parton, sf);
280 }
281 }
282
283 protected:
284
285 size_t _mode;
286
287 private:
288
289 Histo1DPtr _hMu_topPt_parton, _hMu_topY_parton, _hEl_topPt_parton, _hEl_topY_parton, _hComb_topPt_parton, _hComb_topY_parton;
290 Histo1DPtr _hMu_topPt_particle, _hMu_topY_particle, _hEl_topPt_particle, _hEl_topY_particle, _hComb_topPt_particle, _hComb_topY_particle;
291 Histo1DPtr _hMu_topPt_parton_norm, _hMu_topY_parton_norm, _hEl_topPt_parton_norm, _hEl_topY_parton_norm, _hComb_topPt_parton_norm, _hComb_topY_parton_norm;
292 Histo1DPtr _hMu_topPt_particle_norm, _hMu_topY_particle_norm, _hEl_topPt_particle_norm, _hEl_topY_particle_norm, _hComb_topPt_particle_norm, _hComb_topY_particle_norm;
293 Histo1DPtr _hMu_cutflow, _hEl_cutflow;
294
295 double _nMu = 0., _nEl = 0.;
296 double _nPassParton_mu = 0.,_nPassParton_el = 0.;
297 double _nPassParticle_mu = 0., _nPassParticle_el = 0.;
298
299 };
300
301
302 // The hook for the plugin system
303 RIVET_DECLARE_PLUGIN(CMS_2016_I1454211);
304
305}
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