Rivet analyses referenceBESIII_2017_I1607253Cross sections for $e^+e^-\to \phi\phi\phi$ and $\phi\phi\omega$ for energies between 4 and 4.6 GeVExperiment: BESIII (BEPC) Inspire ID: 1607253 Status: VALIDATED NOHEPDATA Authors:
Beam energies: (2.0, 2.0); (2.1, 2.1); (2.1, 2.1); (2.2, 2.2); (2.2, 2.2); (2.3, 2.3) GeV Run details:
Measurement of the cross sections for $e^+e^-\to \phi\phi\phi$ and $\phi\phi\omega$ for energies between 4 and 4.6 GeV Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples. Source code: BESIII_2017_I1607253.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 e+ e- > 2 phi + phi or omega
10 class BESIII_2017_I1607253 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2017_I1607253);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 // projections
23 declare(FinalState(), "FS");
24 declare(UnstableParticles(Cuts::pid==223 || Cuts::pid==333), "UFS");
25 // counters
26 for (unsigned int ix=0; ix<2; ++ix) {
27 book(_sigma[ix], 1+ix, 1, 1);
28 }
29
30 for (const string& en : _sigma[0].binning().edges<0>()) {
31 const double end = std::stod(en)*GeV;
32 if (isCompatibleWithSqrtS(end)) {
33 _ecms = en;
34 break;
35 }
36 }
37 if (_ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
38 }
39
40 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
41 for (const Particle &child : p.children()) {
42 if (child.children().empty()) {
43 --nRes[child.pid()];
44 --ncount;
45 }
46 else {
47 findChildren(child,nRes,ncount);
48 }
49 }
50 }
51
52 /// Perform the per-event analysis
53 void analyze(const Event& event) {
54 const FinalState& fs = apply<FinalState>(event, "FS");
55 map<long,int> nCount;
56 int ntotal(0);
57 for (const Particle& p: fs.particles()) {
58 nCount[p.pid()] += 1;
59 ++ntotal;
60 }
61 const FinalState& ufs = apply<FinalState>(event, "UFS");
62 Particles phi = ufs.particles(Cuts::pid==333);
63 Particles omega = ufs.particles(Cuts::pid==223);
64 if (phi.size()<2) vetoEvent;
65 bool found = false;
66 // first phi
67 for (unsigned int ix=0; ix<phi.size(); ++ix) {
68 const Particle & phi1 = phi[ix];
69 if(phi1.children().empty()) continue;
70 map<long,int> nRes = nCount;
71 int ncount = ntotal;
72 findChildren(phi1,nRes,ncount);
73 // second phi
74 for (unsigned int iy=ix+1; iy<phi.size(); ++iy) {
75 const Particle & phi2 = phi[iy];
76 if (phi2.children().empty()) continue;
77 map<long,int> nRes2 = nRes;
78 int ncount2 = ncount;
79 findChildren(phi2,nRes2,ncount2);
80 // search for third phi
81 for (unsigned int iz=iy+1; iz<phi.size(); ++iz) {
82 const Particle & phi3 = phi[iz];
83 if (phi3.children().empty()) continue;
84 map<long,int> nRes3 = nRes2;
85 int ncount3 = ncount2;
86 findChildren(phi3,nRes3,ncount3);
87 found = true;
88 for (const auto& val : nRes3) {
89 if (val.second!=0) {
90 found = false;
91 break;
92 }
93 }
94 if(found) {
95 _sigma[1]->fill(_ecms);
96 break;
97 }
98 }
99 if (found) break;
100 // search for omega
101 for (unsigned int iz=0; iz<omega.size(); ++iz) {
102 const Particle& omega1 = omega[iz];
103 if (omega1.children().empty()) continue;
104 map<long,int> nRes3 = nRes2;
105 int ncount3 = ncount2;
106 findChildren(omega1,nRes3,ncount3);
107 found = true;
108 for (const auto& val : nRes3) {
109 if (val.second!=0) {
110 found = false;
111 break;
112 }
113 }
114 if (found) {
115 _sigma[0]->fill(_ecms);
116 break;
117 }
118 }
119 if(found) break;
120 }
121 if (found) break;
122 }
123 }
124
125
126 /// Normalise histograms etc., after the run
127 void finalize() {
128 scale(_sigma, crossSection()/ sumOfWeights() /femtobarn);
129 }
130
131 /// @}
132
133
134 /// @name Histograms
135 /// @{
136 BinnedHistoPtr<string> _sigma[2];
137 string _ecms;
138 /// @}
139
140
141 };
142
143
144 RIVET_DECLARE_PLUGIN(BESIII_2017_I1607253);
145
146}
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