Rivet analyses referenceCMD2_2000_I532970Cross section for $e^+e^-\to\pi^+\pi^+\pi^-\pi^+\pi^0$ between 1.28 and 1.38 GeVExperiment: CMD2 (VEPP-2M) Inspire ID: 532970 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the cross section for $e^+e^-\to\pi^+\pi^+\pi^-\pi^+\pi^0$ between 1.28 and 1.38 GeV. Source code: CMD2_2000_I532970.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 Add a short analysis description here
10 class CMD2_2000_I532970 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_2000_I532970);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22
23 // Initialise and register projections
24 declare(FinalState(), "FS");
25 declare(UnstableParticles(), "UFS");
26 book(_numOmegaPiPi, "TMP/OmegaPiPi");
27 book(_numEtaPiPi, "TMP/EtaPiPi");
28 book(_num5Pi, "TMP/5Pi");
29
30 }
31
32 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
33 for (const Particle &child : p.children()) {
34 if(child.children().empty()) {
35 --nRes[child.pid()];
36 --ncount;
37 }
38 else
39 findChildren(child,nRes,ncount);
40 }
41 }
42
43 /// Perform the per-event analysis
44 void analyze(const Event& event) {
45
46 const FinalState& fs = apply<FinalState>(event, "FS");
47
48 map<long,int> nCount;
49 int ntotal(0);
50 for (const Particle& p : fs.particles()) {
51 nCount[p.pid()] += 1;
52 ++ntotal;
53 }
54 const FinalState& ufs = apply<FinalState>(event, "UFS");
55 bool foundRes = false;
56 for (const Particle& p : ufs.particles()) {
57 if(p.children().empty()) continue;
58 // find the eta
59 if(p.pid()==221) {
60 map<long,int> nRes = nCount;
61 int ncount = ntotal;
62 findChildren(p,nRes,ncount);
63 // eta pi+pi-
64 if(ncount!=2) continue;
65 bool matched = true;
66 for(auto const & val : nRes) {
67 if(abs(val.first)==211) {
68 if(val.second !=1) {
69 matched = false;
70 break;
71 }
72 }
73 else if(val.second!=0) {
74 matched = false;
75 break;
76 }
77 }
78 if(matched) {
79 _numEtaPiPi->fill();
80 foundRes = true;
81 }
82 }
83 // find the omega
84 else if(p.pid()==223) {
85 map<long,int> nRes = nCount;
86 int ncount = ntotal;
87 findChildren(p,nRes,ncount);
88 // eta pi+pi-
89 if(ncount!=2) continue;
90 bool matched = true;
91 for(auto const & val : nRes) {
92 if(abs(val.first)==211) {
93 if(val.second !=1) {
94 matched = false;
95 break;
96 }
97 }
98 else if(val.second!=0) {
99 matched = false;
100 break;
101 }
102 }
103 if(matched) {
104 _numOmegaPiPi->fill();
105 foundRes = true;
106 }
107 }
108 }
109
110 if(foundRes) vetoEvent;
111 if(nCount[-211]==2&&nCount[211]==2&&nCount[111]==1)
112 _num5Pi->fill();
113 }
114
115 /// Normalise histograms etc., after the run
116 void finalize() {
117 for (unsigned int ix=1;ix<4;++ix) {
118 double sigma,error;
119 if(ix==1) {
120 sigma = _numOmegaPiPi->val();
121 error = _numOmegaPiPi->err();
122 }
123 else if(ix==2) {
124 sigma = _numEtaPiPi->val();
125 error = _numEtaPiPi->err();
126 }
127 else {
128 sigma = _num5Pi->val();
129 error = _num5Pi->err();
130 }
131 sigma *= crossSection()/ sumOfWeights() /nanobarn;
132 error *= crossSection()/ sumOfWeights() /nanobarn;
133 Estimate1DPtr mult;
134 book(mult, ix, 1, 1);
135 for (auto& b : mult->bins()) {
136 if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
137 b.set(sigma, error);
138 }
139 }
140 }
141 }
142
143 /// @}
144
145 /// @name Histograms
146 /// @{
147 CounterPtr _numEtaPiPi,_numOmegaPiPi,_num5Pi;
148 /// @}
149
150 };
151
152
153 RIVET_DECLARE_PLUGIN(CMD2_2000_I532970);
154
155
156}
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