Rivet analyses referenceATLAS_2014_I1315949Distributions sensitive to the underlying event in inclusive Z-boson production at 7 TeVExperiment: ATLAS (LHC) Inspire ID: 1315949 Status: VALIDATED Authors:
Beam energies: (3500.0, 3500.0) GeV Run details:
Charged-particle distributions sensitive to the properties of the underlying event are measured for an inclusive sample of events containing a $Z$-boson, decaying to an electron or muon pair. The measurement is based on data collected using the ATLAS detector at the LHC in proton--proton collisions at a centre-of-mass energy of 7 TeV with an integrated luminosity of 4.6 fb$^{-1}$. Distributions of the charged particle multiplicity and of the charged particle transverse momentum are measured in regions of azimuthal angle defined with respect to the $Z$-boson direction. Source code: ATLAS_2014_I1315949.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/ChargedFinalState.hh"
5#include "Rivet/Projections/DileptonFinder.hh"
6
7namespace Rivet {
8
9
10 class ATLAS_2014_I1315949 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2014_I1315949);
15
16 void init() {
17
18 DileptonFinder zfinder(91.2*GeV, 0.1, Cuts::abseta < 2.4 && Cuts::pT > 20*GeV && Cuts::abspid == PID::MUON, Cuts::massIn(66*GeV, 116*GeV));
19 declare(zfinder, "DileptonFinder");
20
21 ChargedFinalState cfs( zfinder.remainingFinalState() );
22 declare(cfs, "cfs");
23
24
25 book(_h_pTsum_tow , 67, 1, 1);
26 book(_h_pTsum_trv , 68, 1, 1);
27 book(_h_pTsum_away , 69, 1, 1);
28 book(_h_pTsum_tmin , 70, 1, 1);
29 book(_h_pTsum_tmax , 71, 1, 1);
30 book(_h_pTsum_tdif ,125, 1, 1);
31
32 book(_h_Nchg_tow , 72, 1, 1);
33 book(_h_Nchg_trv , 73, 1, 1);
34 book(_h_Nchg_away , 74, 1, 1);
35 book(_h_Nchg_tmin , 75, 1, 1);
36 book(_h_Nchg_tmax , 82, 1, 1);
37 book(_h_Nchg_tdif ,126, 1, 1);
38
39 book(_h_pTavg_tow ,113, 1, 1);
40 book(_h_pTavg_trv ,114, 1, 1);
41 book(_h_pTavg_away ,115, 1, 1);
42
43 book(_h_pTavgvsmult_tow , 116, 1, 1);
44 book(_h_pTavgvsmult_trv , 117, 1, 1);
45 book(_h_pTavgvsmult_away, 118, 1, 1);
46
47
48 // Book sumpt and nch histos
49 for (size_t id = 0; id < 6.; ++id) {
50 book(_h_ptSum_1D[0][id], 76 + id, 1, 1);
51 book(_h_ptSum_1D[1][id],107 + id, 1, 1);
52 book(_h_ptSum_1D[2][id],119 + id, 1, 1);
53 book(_h_ptSum_1D[3][id],127 + id, 1, 1);
54 book(_h_Nchg_1D[0][id], 83 + id, 1, 1);
55 book(_h_Nchg_1D[1][id], 89 + id, 1, 1);
56 book(_h_Nchg_1D[2][id], 95 + id, 1, 1);
57 book(_h_Nchg_1D[3][id], 101 + id, 1, 1);
58 }
59 }
60
61
62 /// Perform the per-event analysis
63 void analyze(const Event& event) {
64
65 const DileptonFinder& zfinder = apply<DileptonFinder>(event, "DileptonFinder");
66
67 if (zfinder.bosons().size() != 1) vetoEvent;
68
69 double Zpt = zfinder.bosons()[0].momentum().pT()/GeV;
70 double Zphi = zfinder.bosons()[0].momentum().phi(MINUSPI_PLUSPI);
71 double Zmass = zfinder.bosons()[0].momentum().mass()/GeV;
72 if(Zmass < 66. || Zmass > 116.) vetoEvent;
73
74 // Initialise counters for Nch and sumPt for all regions
75 int nTowards(0), nTransverse(0), nLeft(0), nRight(0), nTrmin(0), nTrmax(0), nAway(0);
76 double ptSumTowards(0.0), ptSumTransverse(0.0), ptSumLeft(0.0), ptSumRight(0.0),
77 ptSumTrmin(0.0), ptSumTrmax(0.0), ptSumAway(0.0);
78
79 // The charged particles
80 Particles particles = apply<ChargedFinalState>(event, "cfs").particlesByPt(
81 Cuts::pT > 0.5*GeV && Cuts::abseta <2.5);
82
83 // Loop over charged particles with pT>500 MeV and |eta|<2.5
84 for (const Particle& p : particles) {
85 double dphi = p.momentum().phi(MINUSPI_PLUSPI) - Zphi;
86 double pT = p.momentum().pT();
87
88 // Get multiples of 2pi right
89 for(; std::fabs(dphi) > M_PI; dphi += (dphi > 0. ? -2.*M_PI : 2.*M_PI) );
90
91 // Towards region
92 if( std::fabs(dphi) < M_PI/3. ) {
93 nTowards++;
94 ptSumTowards += pT;
95 }
96 // Transverse region
97 else if( std::fabs(dphi) < 2.*M_PI/3. ) {
98 nTransverse++;
99 ptSumTransverse += pT;
100 if(dphi > 0.) {
101 nRight++;
102 ptSumRight += pT;
103 }
104 else {
105 nLeft++;
106 ptSumLeft += pT;
107 }
108 }
109 // Away region
110 else {
111 nAway++;
112 ptSumAway += pT;
113 }
114 }
115
116 // TransMAX, TransMIN regions
117 if (ptSumLeft > ptSumRight) {
118 ptSumTrmax = ptSumLeft;
119 ptSumTrmin = ptSumRight;
120 nTrmax = nLeft;
121 nTrmin = nRight;
122 }
123 else {
124 ptSumTrmax = ptSumRight;
125 ptSumTrmin = ptSumLeft;
126 nTrmax = nRight;
127 nTrmin = nLeft;
128 }
129
130 // min max regions have difference are than all other regions
131 const double area = 5.*2./3.*M_PI;
132
133 // Fill sumPt vs. Zpt region profiles
134 _h_pTsum_tow->fill( Zpt, ptSumTowards/area);
135 _h_pTsum_trv->fill( Zpt, ptSumTransverse/area);
136 _h_pTsum_away->fill(Zpt, ptSumAway/area);
137 _h_pTsum_tmin->fill(Zpt, ptSumTrmin/(0.5*area));
138 _h_pTsum_tmax->fill(Zpt, ptSumTrmax/(0.5*area));
139 _h_pTsum_tdif->fill(Zpt, (ptSumTrmax - ptSumTrmin)/(0.5*area));
140
141 // Fill Nch vs. Zpt region profiles
142 _h_Nchg_tow->fill( Zpt, nTowards/area);
143 _h_Nchg_trv->fill( Zpt, nTransverse/area);
144 _h_Nchg_away->fill(Zpt, nAway/area);
145 _h_Nchg_tmin->fill(Zpt, nTrmin/(0.5*area));
146 _h_Nchg_tmax->fill(Zpt, nTrmax/(0.5*area));
147 _h_Nchg_tdif->fill(Zpt, (nTrmax - nTrmin)/(0.5*area));
148
149
150 // Fill <pT> vs. ZpT profiles
151 _h_pTavg_tow->fill( Zpt, nTowards > 0.? ptSumTowards/nTowards : 0.);
152 _h_pTavg_trv->fill( Zpt, nTransverse > 0.? ptSumTransverse/nTransverse : 0.);
153 _h_pTavg_away->fill(Zpt, nAway > 0.? ptSumAway/nAway : 0.);
154
155 // Fill <Nch> vs. ZpT profiles
156 _h_pTavgvsmult_tow->fill( nTowards, nTowards > 0.? ptSumTowards/nTowards : 0.);
157 _h_pTavgvsmult_trv->fill( nTransverse, nTransverse > 0.? ptSumTransverse/nTransverse : 0.);
158 _h_pTavgvsmult_away->fill(nAway, nAway > 0.? ptSumAway/nAway : 0.);
159
160 // Determine Zpt region histo to fill
161 int i_bin(0);
162 if (inRange(Zpt,0,5) ) i_bin=0;
163 if (inRange(Zpt,5,10) ) i_bin=1;
164 if (inRange(Zpt,10,20) ) i_bin=2;
165 if (inRange(Zpt,20,50) ) i_bin=3;
166 if (inRange(Zpt,50,110) ) i_bin=4;
167 if (Zpt>110) i_bin=5;
168
169 // SumPt histos for Zpt region
170 _h_ptSum_1D[0][i_bin]->fill(ptSumTowards/area);
171 _h_ptSum_1D[1][i_bin]->fill(ptSumTransverse/area);
172 _h_ptSum_1D[2][i_bin]->fill(ptSumTrmin/(0.5*area));
173 _h_ptSum_1D[3][i_bin]->fill(ptSumTrmax/(0.5*area));
174
175 // Nch histos for Zpt region
176 _h_Nchg_1D[0][i_bin]->fill(nTowards/area);
177 _h_Nchg_1D[1][i_bin]->fill(nTransverse/area);
178 _h_Nchg_1D[2][i_bin]->fill(nTrmin/(0.5*area));
179 _h_Nchg_1D[3][i_bin]->fill(nTrmax/(0.5*area));
180 }
181
182
183 /// Normalise histograms etc., after the run
184 void finalize() {
185 for(int i_reg = 0; i_reg < 4; i_reg++) {
186 for(int i_bin = 0; i_bin < 6; i_bin++) {
187 normalize( _h_ptSum_1D[i_reg][i_bin] );
188 normalize( _h_Nchg_1D[ i_reg][i_bin] );
189 }
190 }
191 }
192
193
194 private:
195
196 Profile1DPtr _h_pTsum_tow,
197 _h_pTsum_trv,
198 _h_pTsum_away,
199 _h_pTsum_tmin,
200 _h_pTsum_tmax,
201 _h_pTsum_tdif,
202
203 _h_Nchg_tow,
204 _h_Nchg_trv,
205 _h_Nchg_away,
206 _h_Nchg_tmin,
207 _h_Nchg_tmax,
208 _h_Nchg_tdif,
209
210 _h_pTavg_tow,
211 _h_pTavg_trv,
212 _h_pTavg_away,
213 _h_pTavgvsmult_tow,
214 _h_pTavgvsmult_trv,
215 _h_pTavgvsmult_away;
216
217 Histo1DPtr _h_ptSum_1D[4][6], _h_Nchg_1D[4][6];
218
219
220 };
221
222
223 RIVET_DECLARE_PLUGIN(ATLAS_2014_I1315949);
224
225}
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