Rivet analyses referenceAMY_1995_I406129Durham and Jade differential 2-jet rate at 57.7 GeVExperiment: AMY (Tristan) Inspire ID: 406129 Status: VALIDATED Authors:
Beam energies: (28.9, 28.9) GeV Run details:
Measurement of the differential 2-jet rate in $e^+e^-$ collisions at $57.7$ GeV by the AMY Collaboration. The Durham algorithm, together with 3 variants of the JADE algorithm are used. The JADE E-scheme results are significantly different from the other approaches. Source code: AMY_1995_I406129.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/FastJets.hh"
5#include "fastjet/JadePlugin.hh"
6
7namespace fastjet {
8
9class P_scheme : public JetDefinition::Recombiner {
10 public:
11 std::string description() const {return "";}
12 void recombine(const PseudoJet & pa, const PseudoJet & pb,
13 PseudoJet & pab) const {
14 PseudoJet tmp = pa + pb;
15 double E = sqrt(tmp.px()*tmp.px() + tmp.py()*tmp.py() + tmp.pz()*tmp.pz());
16 pab.reset_momentum(tmp.px(), tmp.py(), tmp.pz(), E);
17 }
18 void preprocess(PseudoJet & p) const {
19 double E = sqrt(p.px()*p.px() + p.py()*p.py() + p.pz()*p.pz());
20 p.reset_momentum(p.px(), p.py(), p.pz(), E);
21 }
22 ~P_scheme() { }
23};
24
25class E0_scheme : public JetDefinition::Recombiner {
26 public:
27 std::string description() const {return "";}
28 void recombine(const PseudoJet & pa, const PseudoJet & pb,
29 PseudoJet & pab) const {
30 PseudoJet tmp = pa + pb;
31 double fact = tmp.E()/sqrt(tmp.px()*tmp.px()+tmp.py()*tmp.py()+tmp.pz()*tmp.pz());
32 pab.reset_momentum(fact*tmp.px(), fact*tmp.py(), fact*tmp.pz(), tmp.E());
33 }
34 void preprocess(PseudoJet & p) const {
35 double fact = p.E()/sqrt(p.px()*p.px()+p.py()*p.py()+p.pz()*p.pz());
36
37 p.reset_momentum(fact*p.px(), fact*p.py(), fact*p.pz(), p.E());
38 }
39 ~E0_scheme() { }
40};
41
42}
43
44
45namespace Rivet {
46
47
48 /// @brief AMY jets at
49 class AMY_1995_I406129 : public Analysis {
50 public:
51
52 /// Constructor
53 RIVET_DEFAULT_ANALYSIS_CTOR(AMY_1995_I406129);
54
55
56 /// @name Analysis methods
57 /// @{
58
59 /// Book histograms and initialise projections before the run
60 void init() {
61 // Initialise and register projections
62 FinalState fs;
63 declare(fs, "FS");
64 // Book histograms
65 book(_h["jade_P"], 2, 1, 1);
66 book(_h["jade_E"], 3, 1, 1);
67 book(_h["jade_E0"], 6, 1, 1);
68 book(_h["durham"], 4, 1, 1);
69 }
70
71
72 /// Perform the per-event analysis
73 void analyze(const Event& event) {
74 Particles particles = apply<FinalState>(event, "FS").particles();
75 MSG_DEBUG("Num particles = " << particles.size());
76 PseudoJets pjs;
77 double mpi=.13957;
78 for (const Particle & p : particles) {
79 Vector3 mom = p.p3();
80 double energy = p.E();
81 if(PID::isCharged(p.pid())) {
82 energy = sqrt(mom.mod2()+sqr(mpi));
83 }
84 else {
85 double fact = energy/mom.mod();
86 mom *=fact;
87 }
88 pjs.push_back(fastjet::PseudoJet(mom.x(),mom.y(),mom.z(),energy));
89 }
90 // durham
91 fastjet::JetDefinition durDef(fastjet::ee_kt_algorithm, fastjet::E_scheme);
92 fastjet::ClusterSequence durham(pjs,durDef);
93 double y_23 = durham.exclusive_ymerge_max(2);
94 string label = _h["durham"]->xEdges()[durhamAxis.index(y_23)-1];
95 _h["durham"]->fill(label);
96 // jade e-scheme
97 fastjet::JetDefinition::Plugin *plugin = new fastjet::JadePlugin();
98 fastjet::JetDefinition jadeEDef(plugin);
99 jadeEDef.set_recombination_scheme(fastjet::E_scheme);
100 fastjet::ClusterSequence jadeE(pjs,jadeEDef);
101 y_23 = jadeE.exclusive_ymerge_max(2);
102 label = _h["jade_E"]->xEdges()[jadeAxis.index(y_23)-1];
103 _h["jade_E"]->fill(label);
104 // jade p-scheme
105 fastjet::P_scheme p_scheme;
106 fastjet::JetDefinition jadePDef(plugin);
107 jadePDef.set_recombiner(&p_scheme);
108 fastjet::ClusterSequence jadeP(pjs,jadePDef);
109 y_23 = jadeP.exclusive_ymerge_max(2);
110 label = _h["jade_P"]->xEdges()[jadeAxis.index(y_23)-1];
111 _h["jade_P"]->fill(label);
112 // jade E0-scheme
113 fastjet::E0_scheme e0_scheme;
114 fastjet::JetDefinition jadeE0Def(plugin);
115 jadeE0Def.set_recombiner(&e0_scheme);
116 fastjet::ClusterSequence jadeE0(pjs,jadeE0Def);
117 y_23 = jadeE0.exclusive_ymerge_max(2);
118 label = _h["jade_E0"]->xEdges()[jadeAxis.index(y_23)-1];
119 _h["jade_E0"]->fill(label);
120 }
121
122
123 /// Normalise histograms etc., after the run
124 void finalize() {
125 scale(_h, 1./sumOfWeights());
126 }
127
128 /// @}
129
130
131 /// @name Histograms
132 /// @{
133 map<string,BinnedHistoPtr<string>> _h;
134 YODA::Axis<double> jadeAxis{0.0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.0825, 0.1,
135 0.12, 0.14, 0.16, 0.1825, 0.21, 0.24, 0.27, 0.3};
136 YODA::Axis<double> durhamAxis{0.0, 0.002, 0.004, 0.0065, 0.0115, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07,
137 0.0825, 0.1, 0.12, 0.14, 0.16, 0.1825, 0.21, 0.24, 0.27, 0.3};
138 /// @}
139
140
141 };
142
143
144 RIVET_DECLARE_PLUGIN(AMY_1995_I406129);
145
146
147}
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