Rivet analyses referenceATLAS_2019_I1734263WW production at 13 TeVExperiment: ATLAS (LHC) Inspire ID: 1734263 Status: VALIDATED Authors:
Beam energies: (6500.0, 6500.0) GeV Run details:
A measurement of fiducial and differential cross-sections for $W^+W^-$ production in proton--proton collisions at $\sqrt{s}=$13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of $36.1$ fb$^{-1}$ is presented. Events with one electron and one muon are selected, corresponding to the decay of the diboson system as $WW\rightarrow e^{\pm}\nu\mu^{\mp}\nu$. To suppress top-quark background, events containing jets with a transverse momentum exceeding 35 GeV are not included in the measurement phase space. The fiducial cross-section, six differential distributions and the cross-section as a function of the jet-veto transverse momentum threshold are measured and compared with several theoretical predictions. Constraints on anomalous electroweak gauge boson self-interactions are also presented in the framework of a dimension-six effective field theory. Source code: ATLAS_2019_I1734263.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FastJets.hh"
4#include "Rivet/Projections/FinalState.hh"
5#include "Rivet/Projections/MissingMomentum.hh"
6#include "Rivet/Projections/PromptFinalState.hh"
7#include "Rivet/Projections/LeptonFinder.hh"
8#include "Rivet/Projections/VetoedFinalState.hh"
9
10namespace Rivet {
11
12
13 /// @brief WW production at 13 TeV
14 class ATLAS_2019_I1734263 : public Analysis {
15 public:
16
17 /// Constructor
18 RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2019_I1734263);
19
20
21 /// @name Analysis methods
22 /// @{
23
24 /// Book histograms and initialise projections before the run
25 void init() {
26
27 const FinalState fs(Cuts::abseta < 5.);
28
29 // Project photons for dressing
30 FinalState photon_id(Cuts::abspid == PID::PHOTON);
31
32 // Cuts for leptons
33 Cut lepton_cuts = (Cuts::abseta < 2.5) && (Cuts::pT > 27*GeV);
34 // Lepton for simplified phase space (e.g. for comparison with CMS)
35 Cut lepton_cuts_simpl = (Cuts::abseta < 2.5) && (Cuts::pT > 25*GeV);
36
37 // Project dressed leptons (e/mu not from tau) with pT > 27 GeV and |eta| < 2.5
38 // Both for normal and simplified phase space
39 PromptFinalState lep_bare(Cuts::abspid == PID::MUON || Cuts::abspid == PID::ELECTRON);
40 LeptonFinder lep_dressed(lep_bare, photon_id, 0.1, lepton_cuts);
41 declare(lep_dressed,"lep_dressed");
42 LeptonFinder lep_dressed_simpl(lep_bare, photon_id, 0.1, lepton_cuts_simpl);
43 declare(lep_dressed_simpl,"lep_dressed_simpl");
44
45 // Get MET
46 MissingMomentum mm(fs);
47 declare(mm, "met");
48
49 // Define hadrons as everything but dressed leptons (for jet clustering)
50 VetoedFinalState hadrons(fs);
51 hadrons.addVetoOnThisFinalState(lep_dressed);
52 declare(hadrons, "hadrons");
53 VetoedFinalState hadrons_simpl(fs);
54 hadrons_simpl.addVetoOnThisFinalState(lep_dressed_simpl);
55 declare(hadrons_simpl, "hadrons_simpl");
56
57 // Project jets
58 FastJets jets(hadrons, JetAlg::ANTIKT, 0.4, JetMuons::ALL, JetInvisibles::NONE);
59 declare(jets, "jets");
60 FastJets jets_simpl(hadrons_simpl, JetAlg::ANTIKT, 0.4, JetMuons::ALL, JetInvisibles::NONE);
61 declare(jets_simpl, "jets_simpl");
62
63
64 // Book histograms
65 // fiducial differential cross section as a function of the jet-veto pt cut
66 book(_d, 1, 1, 1);
67
68 // fiducial differential cross section (leading lepton pt)
69 book(_h["ptlead"], 4, 1, 1);
70 book(_h["ptlead_norm"], 22, 1, 1);
71 book(_h["ptlead_simpl"], 41, 1, 1);
72
73 // fiducial differential cross section (dilepton-system mll)
74 book(_h["mll"], 7, 1, 1);
75 book(_h["mll_norm"], 25, 1, 1);
76 book(_h["mll_simpl"], 42, 1, 1);
77
78 // fiducial differential cross section (dilepton-system ptll)
79 book(_h["ptll"], 10, 1, 1);
80 book(_h["ptll_norm"], 28, 1, 1);
81 book(_h["ptll_simpl"], 43, 1, 1);
82
83 // fiducial differential cross section (absolute rapidity of dilepton-system y_ll)
84 book(_h["yll"], 13, 1, 1);
85 book(_h["yll_norm"], 31, 1, 1);
86
87 // fiducial differential cross section (dilepton-system delta_phi_ll)
88 book(_h["dphill"], 16, 1, 1);
89 book(_h["dphill_norm"], 34, 1, 1);
90
91
92 // fiducial differential cross section (absolute costheta* of dilepton-system costhetastar_ll)
93 book(_h["costhetastarll"], 19, 1, 1);
94 book(_h["costhetastarll_norm"], 37, 1, 1);
95
96 }
97
98
99 /// Perform the per-event analysis
100 void analyze(const Event& event) {
101
102 // Get met and find leptons
103 const MissingMomentum& met = apply<MissingMomentum>(event, "met");
104 const DressedLeptons &leptons = apply<LeptonFinder>(event, "lep_dressed").dressedLeptons();
105 const DressedLeptons &leptons_simpl = apply<LeptonFinder>(event, "lep_dressed_simpl").dressedLeptons();
106
107 // Find jets and jets for simplified phase space (for the latter slightly different leptons are excluded from clustering)
108 const Jets& jets30 = apply<FastJets>(event, "jets").jetsByPt(Cuts::abseta < 4.5 && Cuts::pT > 30*GeV);
109 const Jets& jets_simpl = apply<FastJets>(event, "jets_simpl").jetsByPt(Cuts::abseta < 4.5 && Cuts::pT > 30*GeV);
110
111 // Define observables
112 const FourMomentum dilep = leptons.size()>1 ? leptons[0].momentum() + leptons[1].momentum() : FourMomentum(0,0,0,0);
113 const double ptll = leptons.size()>1 ? dilep.pT()/GeV : -1;
114 const double Mll = leptons.size()>1 ? dilep.mass()/GeV : -1;
115 const double Yll = leptons.size()>1 ? dilep.absrap() : -5;
116 const double DPhill = leptons.size()>1 ? fabs(deltaPhi(leptons[0], leptons[1])) : -1.;
117 const double costhetastar = leptons.size()>1 ? fabs(tanh((leptons[0].eta() - leptons[1].eta()) / 2)) : -0.2;
118
119 // Define observables for simplified PS
120 const FourMomentum dilep_simpl = leptons_simpl.size()>1 ? leptons_simpl[0].momentum() + leptons_simpl[1].momentum() : FourMomentum(0,0,0,0);
121 const double ptll_simpl = leptons_simpl.size()>1 ? dilep_simpl.pT()/GeV : -1;
122 const double Mll_simpl = leptons_simpl.size()>1 ? dilep_simpl.mass()/GeV : -1;
123
124 // Cuts for simplified PS
125 bool veto_simpl = false;
126 // Remove events that do not contain 2 good leptons (either muons or electrons)
127 if ( leptons_simpl.size() != 2 ) veto_simpl = true;
128 // Veto same-flavour events
129 else if ( leptons_simpl[0].abspid() == leptons_simpl[1].abspid()) veto_simpl = true;
130 // Veto same-charge events
131 else if ( leptons_simpl[0].pid()*leptons_simpl[1].pid()>0) veto_simpl = true;
132 // MET (pt-MET) cut
133 else if (met.missingPt() <= 20*GeV) veto_simpl = true;
134 // jetveto
135 else if ( !jets_simpl.empty() ) veto_simpl = true;
136
137 // Fill histos for simplified phase space
138 if ( !veto_simpl ){
139 _h["ptlead_simpl"]->fill(leptons_simpl[0].pT()/GeV);
140 _h["ptll_simpl"]->fill(ptll_simpl);
141 _h["mll_simpl"]->fill(Mll_simpl);
142 }
143
144
145 // Event selection for proper fiducial phase space
146 // Remove events that do not contain 2 good leptons (either muons or electrons)
147 if ( leptons.size() != 2) vetoEvent;
148 // Veto same-flavour events
149 if ( leptons[0].abspid() == leptons[1].abspid()) vetoEvent;
150 // Veto same-charge events
151 if ( leptons[0].pid()*leptons[1].pid()>0) vetoEvent;
152 // MET (pt-MET) cut
153 if (met.missingPt() <= 20*GeV) vetoEvent;
154 // m_ll cut
155 if (dilep.mass() <= 55*GeV) vetoEvent;
156 // pt_ll cut
157 if (dilep.pT() <= 30*GeV) vetoEvent;
158
159 // Fill cross section as function of veto-jet pt before applying jet veto
160 if (jets30.empty() || jets30[0].pT()/GeV < 30.) _d->fill(30);
161 if (jets30.empty() || jets30[0].pT()/GeV < 35.) _d->fill(35);
162 if (jets30.empty() || jets30[0].pT()/GeV < 40.) _d->fill(40);
163 if (jets30.empty() || jets30[0].pT()/GeV < 45.) _d->fill(45);
164 if (jets30.empty() || jets30[0].pT()/GeV < 50.) _d->fill(50);
165 if (jets30.empty() || jets30[0].pT()/GeV < 55.) _d->fill(55);
166 if (jets30.empty() || jets30[0].pT()/GeV < 60.) _d->fill(60);
167 // Jet veto at 35 GeV is the default
168 if (!jets30.empty() && jets30[0].pT()/GeV > 35.) vetoEvent;
169
170 // fill histograms
171 _h["ptlead"]->fill(leptons[0].pT()/GeV);
172 _h["ptlead_norm"]->fill(leptons[0].pT()/GeV);
173
174 _h["ptll"]->fill(ptll);
175 _h["ptll_norm"]->fill(ptll);
176
177 _h["mll"]->fill(Mll);
178 _h["mll_norm"]->fill(Mll);
179
180 _h["yll"]->fill(Yll);
181 _h["yll_norm"]->fill(Yll);
182
183 _h["dphill"]->fill(DPhill);
184 _h["dphill_norm"]->fill(DPhill);
185
186 _h["costhetastarll"]->fill(costhetastar);
187 _h["costhetastarll_norm"]->fill(costhetastar);
188
189 }
190
191
192 /// Normalise histograms etc., after the run
193 void finalize() {
194 const double sf(crossSection()/femtobarn/sumOfWeights());
195 // scale histogram by binwidth, as bin content is actually a integrated fiducial cross section
196 // scale to cross section
197 scale(_d, sf);
198 for (auto& hist : _h) {
199 scale(hist.second, sf);
200 if (hist.first.find("norm") != string::npos) normalize(hist.second);
201 }
202 }
203
204 /// @}
205
206 private:
207
208 /// @name Histograms
209 /// @{
210 map<string, Histo1DPtr> _h;
211 BinnedHistoPtr<int> _d;
212 /// @}
213
214 };
215
216
217 RIVET_DECLARE_PLUGIN(ATLAS_2019_I1734263);
218
219}
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