Rivet analyses referenceARGUS_1996_I403304γγ→ωω between 1.6 and 3 GeVExperiment: ARGUS (DORIS) Inspire ID: 403304 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the differential cross section for γγ→ωω for 1.6GeV<W<3.0GeV. The cross section is measured as a function of the centre-of-mass energy of the photonic collision using the 2π02π+2π− final state. Source code: ARGUS_1996_I403304.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief gamma gamma -> omega omega
10 class ARGUS_1996_I403304 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1996_I403304);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 // Initialise and register projections
23 declare(FinalState(), "FS");
24 declare(UnstableParticles(), "UFS");
25 // book histos
26 if (inRange(sqrtS()/GeV, 1.6, 3.0)) {
27 for (unsigned int ix=0;ix<3;++ix)
28 book(_nMeson[ix],"TMP/nMeson_"+toString(ix+1));
29 }
30 else {
31 throw Error("Invalid CMS energy for ARGUS_1996_I403304");
32 }
33 }
34
35 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
36 for (const Particle &child : p.children()) {
37 if (child.children().empty()) {
38 nRes[child.pid()]-=1;
39 --ncount;
40 }
41 else {
42 findChildren(child,nRes,ncount);
43 }
44 }
45 }
46
47 /// Perform the per-event analysis
48 void analyze(const Event& event) {
49 const FinalState& fs = apply<FinalState>(event, "FS");
50 // find the final-state particles
51 map<long,int> nCount;
52 int ntotal(0);
53 for (const Particle& p : fs.particles()) {
54 nCount[p.pid()] += 1;
55 ++ntotal;
56 }
57 // find omega mesons
58 Particles omega=apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==223);
59 bool nonRes=true;
60 for (unsigned int ix=0; ix<omega.size(); ++ix) {
61 if(omega[ix].children().empty()) continue;
62 map<long,int> nRes=nCount;
63 int ncount = ntotal;
64 findChildren(omega[ix],nRes,ncount);
65 bool matched=false;
66 // omega omega
67 for (unsigned int iy=ix+1; iy<omega.size(); ++iy) {
68 if (omega[iy].children().empty()) continue;
69 map<long,int> nRes2=nRes;
70 int ncount2 = ncount;
71 findChildren(omega[iy],nRes2,ncount2);
72 if (ncount2 !=0 ) continue;
73 matched = true;
74 for (const auto& val : nRes2) {
75 if (val.second!=0) {
76 matched = false;
77 break;
78 }
79 }
80 if (matched) break;
81 }
82 if (matched) {
83 _nMeson[0]->fill();
84 nonRes=false;
85 break;
86 }
87 matched=true;
88 for (const auto& val : nRes) {
89 if (abs(val.first)==211 || val.first==111) {
90 if(val.second!=1) {
91 matched = false;
92 break;
93 }
94 }
95 else {
96 if (val.second!=0) {
97 matched = false;
98 break;
99 }
100 }
101 }
102 if (matched) {
103 nonRes=false;
104 _nMeson[1]->fill();
105 break;
106 }
107 }
108 if (nonRes && ntotal==6 && nCount[PID::PI0]==2 &&
109 nCount[PID::PIPLUS]==2 && nCount[PID::PIMINUS]==2 ) {
110 _nMeson[2]->fill();
111 }
112 }
113
114
115 /// Normalise histograms etc., after the run
116 void finalize() {
117 scale(_nMeson, crossSection()/nanobarn/sumOfWeights());
118 // loop over tables in paper
119 for (unsigned int ix=0; ix<3; ++ix) {
120 Estimate1DPtr mult;
121 book(mult, 1, 1, 1+ix);
122 for (auto& b : mult->bins()) {
123 if (inRange(sqrtS(), b.xMin(), b.xMax())) {
124 b.setVal(_nMeson[ix]->val());
125 b.setErr(_nMeson[ix]->err());
126 }
127 }
128 }
129 }
130
131 /// @}
132
133
134 /// @name Histograms
135 /// @{
136 CounterPtr _nMeson[3];
137 /// @}
138
139
140 };
141
142
143 RIVET_DECLARE_PLUGIN(ARGUS_1996_I403304);
144
145}
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