Rivet analyses referenceATLAS_2018_I1698006Z(vv)+gamma measurement at 13 TeVExperiment: ATLAS (LHC) Inspire ID: 1698006 Status: VALIDATED Authors:
Beam energies: (6500.0, 6500.0) GeV Run details:
The production of Z bosons in association with a high-energy photon (Z$\gamma$ production) is studied in the neutrino decay channel of the Z boson using pp collisions at $\sqrt s$ = 13 TeV. The analysis uses a data sample with an integrated luminosity of 36.1 fb−1 collected by the ATLAS detector at the LHC in 2015 and 2016. Candidate Z$\gamma$ events with invisible decays of the Z boson are selected by requiring significant transverse momentum (pT) of the dineutrino system in conjunction with a single isolated photon with large transverse energy (ET). The rate of Z$\gamma$ production is measured as a function of photon ET, dineutrino system pT and jet multiplicity. Evidence of anomalous triple gauge-boson couplings is sought in Z$\gamma$ production with photo ET greater than 600 GeV. No excess is observed relative to the Standard Model expectation, and upper limits are set on the strength of ZZ$\gamma$ and Z$\gamma\gamma$ couplings. Source code: ATLAS_2018_I1698006.cc 1#include "Rivet/Analysis.hh"
2#include "Rivet/Projections/FinalState.hh"
3#include "Rivet/Projections/FastJets.hh"
4#include "Rivet/Projections/PromptFinalState.hh"
5#include "Rivet/Projections/InvisibleFinalState.hh"
6#include "Rivet/Projections/VetoedFinalState.hh"
7#include "Rivet/Projections/DressedLeptons.hh"
8
9
10
11namespace Rivet {
12
13 /// @brief ATLAS pTmiss+gamma measurement at 13 TeV
14 class ATLAS_2018_I1698006 : public Analysis {
15 public:
16
17 /// Default constructor
18 RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2018_I1698006);
19
20 /// @name Analysis methods
21 //@{
22 void init() {
23
24 // Get options
25 // Default (OFF) uses the extended phase space of the paper.
26 // LVETO ON will add an additonal lepton veto to reject non-Zgamma events
27 // (for conservative BSM limits, for example).
28 _mode = 0;
29 if ( getOption("LVETO") == "ON" ) _mode = 1;
30
31 //prompt photons
32 const Cut photoncut = Cuts::abspid == PID::PHOTON && Cuts::Et > 150*GeV && Cuts::abseta < 2.37;
33 const PromptFinalState photon_fs(photoncut);
34 declare(photon_fs, "Photons");
35
36 //missing energy (prompt neutrinos)
37 declare(InvisibleFinalState(true), "MET");
38
39 if (_mode==1) {
40 FinalState allLeps(Cuts::abspid == PID::ELECTRON || Cuts::abspid == PID::MUON);
41 FinalState photons(Cuts::abspid == PID::PHOTON);
42 PromptFinalState promptLeps(allLeps);
43 Cut dressedLep_cuts = (Cuts::abseta < 2.7) && (Cuts::pT > 7*GeV);
44 const DressedLeptons dressedLeps(photons, promptLeps, 0.1, dressedLep_cuts, true);
45 declare(dressedLeps, "dressedLeptons");
46 }
47
48 //jets. run the jet finder on a final state without the prompt photons, and without neutrinos or muons
49 VetoedFinalState jet_fs(Cuts::abseta > 4.5);
50 jet_fs.addVetoOnThisFinalState(photon_fs);
51 FastJets fastjets(jet_fs, FastJets::ANTIKT, 0.4, JetAlg::Muons::NONE, JetAlg::Invisibles::NONE);
52 declare(fastjets, "Jets");
53
54
55 //books histograms
56 //fig.4a
57 book(_h["Et_inc"],2,1,1);
58 //fig.4b
59 book(_h["Et_exc"],3,1,1);
60 //fig.5a
61 book(_h["pT_inc"],4,1,1);
62 //fig.5b
63 book(_h["pT_exc"],5,1,1);
64 //fig.6
65 book(_h["Njets"],6,1,1);
66
67 }
68
69 void analyze(const Event& event) {
70
71
72 const Particles& photons = apply<PromptFinalState>(event,"Photons").particlesByPt();
73 const Jets& jets = apply<FastJets>(event,"Jets").jetsByPt(Cuts::pT > 50*GeV);
74 const FinalState& metfs = apply<InvisibleFinalState>(event,"MET");
75 Vector3 met_vec;
76 for (const Particle& p : metfs.particles()) met_vec += p.mom().perpVec();
77
78
79 if (_mode==1) {
80 const vector<DressedLepton> &dressedLeptons = apply<DressedLeptons>(event, "dressedLeptons").dressedLeptons();
81 if (dressedLeptons.size() > 0) vetoEvent;
82 }
83
84
85 //Nγ==1 and Emiss > 150 GeV
86 if (met_vec.mod() > 150*GeV && photons.size()==1){
87
88 //inclusive case (Njet>=0)
89 if (jets.size()>=0){
90 bool dR_veto = any(jets, DeltaRLess(photons[0], 0.3));
91 if (not dR_veto) {
92 double Et_photon = photons[0].Et()/GeV;
93 _h["Et_inc"]->fill(Et_photon);
94 //fill in missing energy (neutrino) pT histogram (inclusive)
95 _h["pT_inc"]->fill(met_vec.mod()/GeV);
96 }
97 }
98
99 //exclusive case (Njet==0)
100 if (jets.size() == 0){
101 double Et_photon = photons[0].Et()/GeV;
102 _h["Et_exc"]->fill(Et_photon);
103 //fill in missing energy (neutrino) pT histogram (exclusive)
104 _h["pT_exc"]->fill(met_vec.mod()/GeV);
105 }
106
107 _h["Njets"]->fill(jets.size());
108
109 }
110
111 }
112
113 void finalize() {
114
115 const double sf = crossSection()/femtobarn/sumOfWeights();
116 scale(_h, sf);
117
118 }
119
120 //@}
121
122 private:
123 map<string, Histo1DPtr> _h;
124 size_t _mode;
125
126 };
127
128 // Magic required by the plugin system
129 RIVET_DECLARE_PLUGIN(ATLAS_2018_I1698006);
130
131}
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