Rivet analyses referenceMC_ZVBFMonte Carlo validation observables for VBF $Z[\ell^+ \, \ell^-]$ + 2 jet productionExperiment: () Status: VALIDATED Authors:
Beams: * * Beam energies: ANY Run details:
Available observables are the pT of jets 1-4, jet multiplicity, $\Delta\eta(Z, \text{jet1})$, $\Delta R(\text{jet2}, \text{jet3})$, $m_{jj}$, $H_\text{T}$ and third-jet centrality. Source code: MC_ZVBF.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/DileptonFinder.hh"
4#include "Rivet/Projections/FastJets.hh"
5
6namespace Rivet {
7
8
9 /// @brief MC validation analysis for Zjj events
10 class MC_ZVBF : public Analysis {
11 public:
12
13 /// Default constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(MC_ZVBF);
15
16 /// @name Analysis methods
17 /// @{
18
19 /// Initialize
20 void init() {
21 _dR=0.1;
22 if (getOption("SCHEME") == "BARE") _dR = 0.0;
23 _lepton=PID::ELECTRON;
24 if (getOption("LMODE") == "MU") _lepton = PID::MUON;
25
26 Cut cut = Cuts::abseta < 3.5 && Cuts::pT > 25*GeV;
27 DileptonFinder zfinder(91.2*GeV, _dR, cut && Cuts::abspid == _lepton, Cuts::massIn(65*GeV, 115*GeV));
28 declare(zfinder, "DileptonFinder");
29 FastJets jetpro(zfinder.remainingFinalState(), JetAlg::ANTIKT, 0.4);
30 declare(jetpro, "Jets");
31
32 const double sqrts = sqrtS() ? sqrtS() : 14*TeV;
33 book(_h["gap_inc"], "N_gapjets_inclusive", 8, -0.5, 7.5);
34 book(_h["gap_exc"], "N_gapjets_exclusive", 8, -0.5, 7.5);
35 book(_h["Z_jet1_deta"], "Z_jet1_deta", 50, -5, 5);
36 book(_h["Z_jet1_dR"], "Z_jet1_dR", 25, 0.5, 7.0);
37 book(_h["HT"], "jets_HT", logspace(40, 50, sqrts/GeV/2.0));
38 book(_h["mjj"], "m_jj", 40, 200.0, sqrts/GeV/2.0);
39 book(_h["jve_mjj"], "_jve_mjj", 40, 200.0, sqrts/GeV/2.0);
40 book(_h["pTV"] ,"Z_pT", logspace(100, 1.0, 0.5*sqrts/GeV));
41 book(_h["dphi"], "dphi_jj", 20., -1., 1.);
42 book(_h["drap"], "drap_jj", 20., -10., 10.);
43 book(_h["3JC"], "jet_3_centrality", 25., -2.5, 2.5);
44
45 book(_s["jve_mjj"], "jet_veto_efficiency_mjj");
46
47 for (size_t i = 0; i < 4; ++i) {
48 const string pTname = "jet_pT_" + to_str(i+1);
49 const double pTmax = 1.0/(double(i)+2.0) * sqrts/GeV/2.0;
50 const int nbins_pT = 100/(i+1);
51 if (pTmax > 10) { // Protection aginst logspace exception, needed for LEP
52 book(_h[pTname], pTname, logspace(nbins_pT, 10.0, pTmax));
53 }
54 const string etaname = "jet_eta_" + to_str(i+1);
55 book(_h[etaname], etaname, (i > 1 ? 25 : 50), -5.0, 5.0);
56 const string rapname = "jet_y_" + to_str(i+1);
57 book(_h[rapname], rapname, (i > 1 ? 25 : 50), -5.0, 5.0);
58 const string phiname = "jet_phi_" + to_str(i+1);
59 book(_h[phiname], phiname, (i > 1 ? 25 : 50), -1.0, 1.0);
60 }
61 }
62
63
64 /// Do the analysis
65 void analyze(const Event & e) {
66 MSG_TRACE("MC_ZVBF: running DileptonFinder");
67 const DileptonFinder& zfinder = apply<DileptonFinder>(e, "DileptonFinder");
68 if (zfinder.bosons().size() != 1) vetoEvent;
69 const FourMomentum& zmom = zfinder.bosons()[0].momentum();
70 MSG_TRACE("MC_ZVBF: have exactly one Z boson candidate");
71
72 const Jets& jets = apply<FastJets>(e, "Jets").jetsByPt(Cuts::absrap < 5 && Cuts::pT > 30*GeV);
73 if (jets.size() < 2) {
74 MSG_TRACE("MC_ZVBF: does not have at least two valid jets");
75 vetoEvent;
76 }
77
78 Jet tag1 = jets.at(0);
79 Jet tag2 = jets.at(1);
80 const double mjj = (tag1.mom() + tag2.mom()).mass()/GeV;
81 if (mjj < 200.) {
82 MSG_TRACE("MC_ZVBF: should have at least 200 GeV in Mjj");
83 vetoEvent;
84 }
85
86 // jet kinematics
87 for (size_t i = 0; i < min(4u, jets.size()); ++i) {
88 const string pTname = "jet_pT_" + to_str(i+1);
89 const string etaname = "jet_eta_" + to_str(i+1);
90 const string rapname = "jet_y_" + to_str(i+1);
91 const string phiname = "jet_phi_" + to_str(i+1);
92 _h[pTname]->fill(jets[i].pT()/GeV);
93 _h[etaname]->fill(jets[i].eta());
94 _h[rapname]->fill(jets[i].rap());
95 _h[phiname]->fill(mapAngleMPiToPi(jets[i].phi())/M_PI);
96 }
97
98 size_t n_gap = 0;
99 // start loop at the 3rd hardest pT jet
100 for (size_t i = 2; i < jets.size(); ++i) {
101 const Jet j = jets.at(i);
102 if (isBetween(j, tag1, tag2)) ++n_gap;
103 }
104
105 // gap-jet multiplicities
106 _h["gap_exc"]->fill(n_gap);
107 for (size_t i = 0; i <= 7; ++i) {
108 if (n_gap >= i) {
109 _h["gap_inc"]->fill(i);
110 }
111 }
112
113 _h["jve_mjj"]->fill(mjj);
114 if (n_gap) {
115 // third-jet centrality
116 const double rap1 = jets[0].rap();
117 const double rap2 = jets[1].rap();
118 const double rap3 = jets[2].rap();
119 const double JC = (rap3 - 0.5*(rap1 + rap2))/(rap1 - rap2);
120 _h["3JC"]->fill(JC);
121 }
122 else {
123 MSG_TRACE("MC_ZVBF: should satisfy a CJV");
124 const double HT = sum(jets, Kin::pT, 0.0)/GeV;
125 _h["HT"]->fill(HT);
126 _h["mjj"]->fill(mjj);
127 _h["pTV"]->fill(zmom.pT()/GeV);
128 _h["dphi"]->fill(signedDeltaPhi(tag1, tag2));
129 _h["drap"]->fill(tag1.rap() - tag2.rap());
130
131 // Z tagging jet correlations
132 _h["Z_jet1_deta"]->fill(zmom.eta()-jets[0].eta());
133 _h["Z_jet1_dR"]->fill(deltaR(zmom, jets[0].momentum()));
134 }
135 }
136
137
138 /// Finalize
139 void finalize() {
140 scale(_h, crossSection()/femtobarn/sumOfWeights());
141 efficiency(_h["mjj"], _h["jve_mjj"], _s["jve_mjj"]);
142 }
143
144 /// @}
145
146
147 /// Check if jet is between tagging jets
148 bool isBetween(const Jet &probe, const Jet &boundary1, const Jet &boundary2) {
149 double y_p = probe.rapidity();
150 double y_b1 = boundary1.rapidity();
151 double y_b2 = boundary2.rapidity();
152
153 double y_min = std::min(y_b1, y_b2);
154 double y_max = std::max(y_b1, y_b2);
155
156 return (y_p > y_min && y_p < y_max);
157 }
158
159 double signedDeltaPhi(Jet &j1, Jet &j2) {
160 double dphijj = 0.;
161 if (j1.rap() > j2.rap()) dphijj = j1.phi() - j2.phi();
162 else dphijj = j2.phi() - j1.phi();
163 return mapAngleMPiToPi(dphijj)/M_PI;
164 }
165
166
167 private:
168
169 /// @name Parameters for specialised e/mu and dressed/bare subclassing
170 /// @{
171 double _dR;
172 PdgId _lepton;
173 /// @}
174
175 /// @name Histograms
176 /// @{
177 map<string,Histo1DPtr> _h;
178 map<string,Estimate1DPtr> _s;
179 /// @}
180
181 };
182
183
184 RIVET_DECLARE_PLUGIN(MC_ZVBF);
185
186}
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