Rivet analyses referenceDM2_1992_I339265Cross section for $e^+e^-\to\pi^+\pi^-\pi^0$ and $\omega\pi^+\pi^-$ at energies between 1.35 and 2.4 GeVExperiment: DM2 (DCI) Inspire ID: 339265 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of the cross section for $e^+e^-\to\pi^+\pi^-\pi^0$ and $\omega\pi^+\pi^-$ at energies between 1.35 and 2.4 GeV. Source code: DM2_1992_I339265.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 DM2_1992_I339265 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(DM2_1992_I339265);
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(_n3pi, "TMP/3pi");
27 book(_nomega, "TMP/omega");
28 }
29
30
31 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
32 for (const Particle &child : p.children()) {
33 if(child.children().empty()) {
34 --nRes[child.pid()];
35 --ncount;
36 }
37 else
38 findChildren(child,nRes,ncount);
39 }
40 }
41
42 /// Perform the per-event analysis
43 void analyze(const Event& event) {
44 const FinalState& fs = apply<FinalState>(event, "FS");
45
46 map<long,int> nCount;
47 int ntotal(0);
48 for (const Particle& p : fs.particles()) {
49 nCount[p.pid()] += 1;
50 ++ntotal;
51 }
52 if(ntotal==3 && nCount[211] == 1 && nCount[-211] == 1 && nCount[111] == 1)
53 _n3pi->fill();
54
55 const FinalState& ufs = apply<FinalState>(event, "UFS");
56 for (const Particle& p : ufs.particles()) {
57 if(p.children().empty()) continue;
58 // find the omega
59 if(p.pid()==223) {
60 map<long,int> nRes = nCount;
61 int ncount = ntotal;
62 findChildren(p,nRes,ncount);
63 // omega 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 _nomega->fill();
80 }
81 }
82 }
83
84
85 /// Normalise histograms etc., after the run
86 void finalize() {
87 for (unsigned int ix=1;ix<3;++ix) {
88 double sigma = 0., error = 0.;
89 if(ix==1) {
90 sigma = _n3pi->val();
91 error = _n3pi->err();
92 }
93 else if(ix==2) {
94 sigma = _nomega->val();
95 error = _nomega->err();
96 }
97 sigma *= crossSection()/ sumOfWeights() /nanobarn;
98 error *= crossSection()/ sumOfWeights() /nanobarn;
99 Estimate1DPtr mult;
100 book(mult, ix, 1, 1);
101 for (auto& b : mult->bins()) {
102 if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
103 b.set(sigma, error);
104 }
105 }
106 }
107 }
108
109 /// @}
110
111
112 /// @name Histograms
113 /// @{
114 CounterPtr _n3pi,_nomega;
115 /// @}
116
117
118 };
119
120
121 RIVET_DECLARE_PLUGIN(DM2_1992_I339265);
122
123
124}
|