Rivet analyses referenceATLAS_2011_I945498$Z$+jets in $pp$ at 7 TeVExperiment: ATLAS (LHC) Inspire ID: 945498 Status: VALIDATED Authors:
Beam energies: (3500.0, 3500.0) GeV Run details:
Production of jets in association with a $Z/\gamma^*$ boson in proton--proton collisions at $\sqrt{s} = 7$ TeV with the ATLAS detector. The analysis includes the full 2010 data set, collected with a low rate of multiple proton--proton collisions in the accelerator, corresponding to an integrated luminosity of 36 pb$^{-1}$. Inclusive jet cross sections in $Z/\gamma^*$ events, with $Z/\gamma^*$ decaying into electron or muon pairs, are measured for jets with transverse momentum $p_T > 30$ GeV and jet rapidity $|y| < 4.4$. Source code: ATLAS_2011_I945498.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3
4#include "Rivet/Projections/ZFinder.hh"
5#include "Rivet/Projections/FastJets.hh"
6#include "Rivet/Projections/FinalState.hh"
7#include "Rivet/Projections/VetoedFinalState.hh"
8#include "Rivet/Projections/IdentifiedFinalState.hh"
9#include "Rivet/Projections/LeadingParticlesFinalState.hh"
10
11
12namespace Rivet {
13
14
15 /// ATLAS Z+jets in pp at 7 TeV
16 class ATLAS_2011_I945498 : public Analysis {
17 public:
18
19 /// Constructor
20 ATLAS_2011_I945498()
21 : Analysis("ATLAS_2011_I945498")
22 { }
23
24
25 /// Book histograms and initialise projections before the run
26 void init() {
27
28 // Variable initialisation
29 _isZeeSample = false;
30 _isZmmSample = false;
31 for (size_t chn = 0; chn < 3; ++chn) {
32 book(weights_nj0[chn], "weights_nj0_" + to_str(chn));
33 book(weights_nj1[chn], "weights_nj1_" + to_str(chn));
34 book(weights_nj2[chn], "weights_nj2_" + to_str(chn));
35 book(weights_nj3[chn], "weights_nj3_" + to_str(chn));
36 book(weights_nj4[chn], "weights_nj4_" + to_str(chn));
37 }
38
39 // Set up projections
40 FinalState fs;
41 ZFinder zfinder_mu(fs, Cuts::abseta < 2.4 && Cuts::pT > 20*GeV, PID::MUON, 66*GeV, 116*GeV, 0.1, ZFinder::ClusterPhotons::NODECAY);
42 declare(zfinder_mu, "ZFinder_mu");
43
44 Cut cuts = (Cuts::abseta < 1.37 || Cuts::absetaIn(1.52, 2.47)) && Cuts::pT > 20*GeV;
45
46 ZFinder zfinder_el(fs, cuts, PID::ELECTRON, 66*GeV, 116*GeV, 0.1, ZFinder::ClusterPhotons::NODECAY);
47 declare(zfinder_el, "ZFinder_el");
48
49 Cut cuts25_20 = Cuts::abseta < 2.5 && Cuts::pT > 20*GeV;
50 // For combined cross-sections (combined phase space + dressed level)
51 ZFinder zfinder_comb_mu(fs, cuts25_20, PID::MUON, 66.0*GeV, 116.0*GeV, 0.1, ZFinder::ClusterPhotons::NODECAY);
52 declare(zfinder_comb_mu, "ZFinder_comb_mu");
53 ZFinder zfinder_comb_el(fs, cuts25_20, PID::ELECTRON, 66.0*GeV, 116.0*GeV, 0.1, ZFinder::ClusterPhotons::NODECAY);
54 declare(zfinder_comb_el, "ZFinder_comb_el");
55
56 // Define veto FS in order to prevent Z-decay products entering the jet algorithm
57 VetoedFinalState remfs;
58 remfs.addVetoOnThisFinalState(zfinder_el);
59 remfs.addVetoOnThisFinalState(zfinder_mu);
60 VetoedFinalState remfs_comb;
61 remfs_comb.addVetoOnThisFinalState(zfinder_comb_el);
62 remfs_comb.addVetoOnThisFinalState(zfinder_comb_mu);
63
64 FastJets jets(remfs, FastJets::ANTIKT, 0.4);
65 jets.useInvisibles();
66 declare(jets, "jets");
67 FastJets jets_comb(remfs_comb, FastJets::ANTIKT, 0.4);
68 jets_comb.useInvisibles();
69 declare(jets_comb, "jets_comb");
70
71 // 0=el, 1=mu, 2=comb
72 for (size_t chn = 0; chn < 3; ++chn) {
73 book(_h_njet_incl[chn] ,1, 1, chn+1);
74 book(_h_njet_ratio[chn] ,2, 1, chn+1);
75 book(_h_ptjet[chn] ,3, 1, chn+1);
76 book(_h_ptlead[chn] ,4, 1, chn+1);
77 book(_h_ptseclead[chn] ,5, 1, chn+1);
78 book(_h_yjet[chn] ,6, 1, chn+1);
79 book(_h_ylead[chn] ,7, 1, chn+1);
80 book(_h_yseclead[chn] ,8, 1, chn+1);
81 book(_h_mass[chn] ,9, 1, chn+1);
82 book(_h_deltay[chn] ,10, 1, chn+1);
83 book(_h_deltaphi[chn] ,11, 1, chn+1);
84 book(_h_deltaR[chn] ,12, 1, chn+1);
85 }
86 }
87
88
89 // Jet selection criteria universal for electron and muon channel
90 /// @todo Replace with a Cut passed to jetsByPt
91 Jets selectJets(const ZFinder* zf, const FastJets* allJets) {
92 const FourMomentum l1 = zf->constituents()[0].momentum();
93 const FourMomentum l2 = zf->constituents()[1].momentum();
94 Jets jets;
95 for (const Jet& jet : allJets->jetsByPt(30*GeV)) {
96 const FourMomentum jmom = jet.momentum();
97 if (jmom.absrap() < 4.4 &&
98 deltaR(l1, jmom) > 0.5 && deltaR(l2, jmom) > 0.5) {
99 jets.push_back(jet);
100 }
101 }
102 return jets;
103 }
104
105
106 /// Perform the per-event analysis
107 void analyze(const Event& event) {
108 vector<const ZFinder*> zfs;
109 zfs.push_back(& (apply<ZFinder>(event, "ZFinder_el")));
110 zfs.push_back(& (apply<ZFinder>(event, "ZFinder_mu")));
111 zfs.push_back(& (apply<ZFinder>(event, "ZFinder_comb_el")));
112 zfs.push_back(& (apply<ZFinder>(event, "ZFinder_comb_mu")));
113
114 vector<const FastJets*> fjs;
115 fjs.push_back(& (apply<FastJets>(event, "jets")));
116 fjs.push_back(& (apply<FastJets>(event, "jets_comb")));
117
118 // Determine what kind of MC sample this is
119 const bool isZee = (zfs[0]->bosons().size() == 1) || (zfs[2]->bosons().size() == 1);
120 const bool isZmm = (zfs[1]->bosons().size() == 1) || (zfs[3]->bosons().size() == 1);
121 if (isZee) _isZeeSample = true;
122 if (isZmm) _isZmmSample = true;
123
124 // Require exactly one electronic or muonic Z-decay in the event
125 bool isZeemm = ( (zfs[0]->bosons().size() == 1 && zfs[1]->bosons().size() != 1) ||
126 (zfs[1]->bosons().size() == 1 && zfs[0]->bosons().size() != 1) );
127 bool isZcomb = ( (zfs[2]->bosons().size() == 1 && zfs[3]->bosons().size() != 1) ||
128 (zfs[3]->bosons().size() == 1 && zfs[2]->bosons().size() != 1) );
129 if (!isZeemm && !isZcomb) vetoEvent;
130
131 vector<int> zfIDs;
132 vector<int> fjIDs;
133 if (isZeemm) {
134 int chn = zfs[0]->bosons().size() == 1 ? 0 : 1;
135 zfIDs.push_back(chn);
136 fjIDs.push_back(0);
137 }
138 if (isZcomb) {
139 int chn = zfs[2]->bosons().size() == 1 ? 2 : 3;
140 zfIDs.push_back(chn);
141 fjIDs.push_back(1);
142 }
143
144 for (size_t izf = 0; izf < zfIDs.size(); ++izf) {
145 int zfID = zfIDs[izf];
146 int fjID = fjIDs[izf];
147
148 int chn = zfID;
149 if (zfID == 2 || zfID == 3) chn = 2;
150
151 Jets jets = selectJets(zfs[zfID], fjs[fjID]);
152
153 switch (jets.size()) {
154 case 0:
155 weights_nj0[chn]->fill();
156 break;
157 case 1:
158 weights_nj0[chn]->fill();
159 weights_nj1[chn]->fill();
160 break;
161 case 2:
162 weights_nj0[chn]->fill();
163 weights_nj1[chn]->fill();
164 weights_nj2[chn]->fill();
165 break;
166 case 3:
167 weights_nj0[chn]->fill();
168 weights_nj1[chn]->fill();
169 weights_nj2[chn]->fill();
170 weights_nj3[chn]->fill();
171 break;
172 default: // >= 4
173 weights_nj0[chn]->fill();
174 weights_nj1[chn]->fill();
175 weights_nj2[chn]->fill();
176 weights_nj3[chn]->fill();
177 weights_nj4[chn]->fill();
178 }
179
180 // Require at least one jet
181 if (jets.empty()) continue;
182
183 // Fill jet multiplicities
184 for (size_t ijet = 1; ijet <= jets.size(); ++ijet) {
185 _h_njet_incl[chn]->fill(ijet);
186 }
187
188 // Loop over selected jets, fill inclusive jet distributions
189 for (size_t ijet = 0; ijet < jets.size(); ++ijet) {
190 _h_ptjet[chn]->fill(jets[ijet].pT()/GeV);
191 _h_yjet [chn]->fill(fabs(jets[ijet].rapidity()));
192 }
193
194 // Leading jet histos
195 const double ptlead = jets[0].pT()/GeV;
196 const double yabslead = fabs(jets[0].rapidity());
197 _h_ptlead[chn]->fill(ptlead);
198 _h_ylead [chn]->fill(yabslead);
199
200 if (jets.size() >= 2) {
201 // Second jet histos
202 const double pt2ndlead = jets[1].pT()/GeV;
203 const double yabs2ndlead = fabs(jets[1].rapidity());
204 _h_ptseclead[chn] ->fill(pt2ndlead);
205 _h_yseclead [chn] ->fill(yabs2ndlead);
206
207 // Dijet histos
208 const double deltaphi = fabs(deltaPhi(jets[1], jets[0]));
209 const double deltarap = fabs(jets[0].rapidity() - jets[1].rapidity()) ;
210 const double deltar = fabs(deltaR(jets[0], jets[1], RAPIDITY));
211 const double mass = (jets[0].momentum() + jets[1].momentum()).mass();
212 _h_mass [chn] ->fill(mass/GeV);
213 _h_deltay [chn] ->fill(deltarap);
214 _h_deltaphi[chn] ->fill(deltaphi);
215 _h_deltaR [chn] ->fill(deltar);
216 }
217 }
218 }
219
220
221 /// @name Ratio calculator util functions
222 //@{
223
224 /// Calculate the ratio, being careful about div-by-zero
225 double ratio(double a, double b) {
226 return (b != 0) ? a/b : 0;
227 }
228
229 /// Calculate the ratio error, being careful about div-by-zero
230 double ratio_err(double a, double b) {
231 return (b != 0) ? sqrt(a/sqr(b) + sqr(a)/(b*b*b)) : 0;
232 }
233
234 //@}
235
236
237 void finalize() {
238 // Fill ratio histograms
239 for (size_t chn = 0; chn < 3; ++chn) {
240 _h_njet_ratio[chn]->addPoint(1, ratio(weights_nj1[chn]->val(), weights_nj0[chn]->val()), 0.5, ratio_err(weights_nj1[chn]->val(), weights_nj0[chn]->val()));
241 _h_njet_ratio[chn]->addPoint(2, ratio(weights_nj2[chn]->val(), weights_nj1[chn]->val()), 0.5, ratio_err(weights_nj2[chn]->val(), weights_nj1[chn]->val()));
242 _h_njet_ratio[chn]->addPoint(3, ratio(weights_nj3[chn]->val(), weights_nj2[chn]->val()), 0.5, ratio_err(weights_nj3[chn]->val(), weights_nj2[chn]->val()));
243 _h_njet_ratio[chn]->addPoint(4, ratio(weights_nj4[chn]->val(), weights_nj3[chn]->val()), 0.5, ratio_err(weights_nj4[chn]->val(), weights_nj3[chn]->val()));
244 }
245
246 // Scale other histos
247 for (size_t chn = 0; chn < 3; ++chn) {
248 // For ee and mumu channels: normalize to Njet inclusive cross-section
249 double xs = crossSectionPerEvent()/picobarn;
250 if (chn != 2 && weights_nj0[chn]->val() != 0.) xs = 1.0 / weights_nj0[chn]->val();
251 // For inclusive MC sample(ee/mmu channels together) we want the single-lepton-flavor xsec
252 if (_isZeeSample && _isZmmSample) xs *= 0.5;
253
254 // Special case histogram: always not normalized
255 scale(_h_njet_incl[chn], (chn < 2) ? crossSectionPerEvent()/picobarn : xs);
256
257 scale(_h_ptjet[chn] , xs);
258 scale(_h_ptlead[chn] , xs);
259 scale(_h_ptseclead[chn], xs);
260 scale(_h_yjet[chn] , xs);
261 scale(_h_ylead[chn] , xs);
262 scale(_h_yseclead[chn] , xs);
263 scale(_h_deltaphi[chn] , xs);
264 scale(_h_deltay[chn] , xs);
265 scale(_h_deltaR[chn] , xs);
266 scale(_h_mass[chn] , xs);
267 }
268
269 }
270
271 //@}
272
273
274 private:
275
276 bool _isZeeSample;
277 bool _isZmmSample;
278
279 CounterPtr weights_nj0[3];
280 CounterPtr weights_nj1[3];
281 CounterPtr weights_nj2[3];
282 CounterPtr weights_nj3[3];
283 CounterPtr weights_nj4[3];
284
285 Scatter2DPtr _h_njet_ratio[3];
286 Histo1DPtr _h_njet_incl[3];
287 Histo1DPtr _h_ptjet[3];
288 Histo1DPtr _h_ptlead[3];
289 Histo1DPtr _h_ptseclead[3];
290 Histo1DPtr _h_yjet[3];
291 Histo1DPtr _h_ylead[3];
292 Histo1DPtr _h_yseclead[3];
293 Histo1DPtr _h_deltaphi[3];
294 Histo1DPtr _h_deltay[3];
295 Histo1DPtr _h_deltaR[3];
296 Histo1DPtr _h_mass[3];
297
298 };
299
300
301 RIVET_DECLARE_PLUGIN(ATLAS_2011_I945498);
302
303
304}
|