Rivet analyses referenceSND_2016_I1473343Cross section for $e^+e^-\to\eta\omega$ for energies below 2 GeVExperiment: SND (VEPP-2M) Inspire ID: 1473343 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Cross section for $e^+e^-\to\eta\omega$ for energies below 2 GeV Source code: SND_2016_I1473343.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- -> omega eta
10 class SND_2016_I1473343 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(SND_2016_I1473343);
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(_nOmegaEta, "/TMP/nOmegaEta");
26 }
27
28 void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
29 for (const Particle &child : p.children()) {
30 if(child.children().empty()) {
31 nRes[child.pid()]-=1;
32 --ncount;
33 }
34 else
35 findChildren(child,nRes,ncount);
36 }
37 }
38
39 /// Perform the per-event analysis
40 void analyze(const Event& event) {
41 const FinalState& fs = apply<FinalState>(event, "FS");
42 map<long,int> nCount;
43 int ntotal(0);
44 for (const Particle& p : fs.particles()) {
45 nCount[p.pid()] += 1;
46 ++ntotal;
47 }
48 const FinalState& ufs = apply<FinalState>(event, "UFS");
49 for (const Particle& p : ufs.particles()) {
50 if(p.children().empty()) continue;
51 if(p.pid()!=223) continue;
52 map<long,int> nRes = nCount;
53 int ncount = ntotal;
54 findChildren(p,nRes,ncount);
55 for (const Particle& p2 : ufs.particles()) {
56 if(p2.pid()!=221) continue;
57 map<long,int> nResB = nRes;
58 int ncountB = ncount;
59 findChildren(p2,nResB,ncountB);
60 if(ncountB!=0) continue;
61 bool matched2 = true;
62 for(auto const & val : nResB) {
63 if(val.second!=0) {
64 matched2 = false;
65 break;
66 }
67 }
68 if(matched2) {
69 _nOmegaEta->fill();
70 break;
71 }
72 }
73 }
74 }
75
76
77 /// Normalise histograms etc., after the run
78 void finalize() {
79 double sigma = _nOmegaEta->val();
80 double error = _nOmegaEta->err();
81 sigma *= crossSection()/ sumOfWeights() /nanobarn;
82 error *= crossSection()/ sumOfWeights() /nanobarn;
83 Scatter2D temphisto(refData(1, 1, 1));
84 Scatter2DPtr mult;
85 book(mult, 1, 1, 1);
86 for (size_t b = 0; b < temphisto.numPoints(); b++) {
87 const double x = temphisto.point(b).x();
88 pair<double,double> ex = temphisto.point(b).xErrs();
89 pair<double,double> ex2 = ex;
90 if(ex2.first ==0.) ex2. first=0.0001;
91 if(ex2.second==0.) ex2.second=0.0001;
92 if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
93 mult->addPoint(x, sigma, ex, make_pair(error,error));
94 }
95 else {
96 mult->addPoint(x, 0., ex, make_pair(0.,.0));
97 }
98 }
99 }
100 //@}
101
102
103 /// @name Histograms
104 //@{
105 CounterPtr _nOmegaEta;
106 //@}
107
108
109 };
110
111
112 // The hook for the plugin system
113 RIVET_DECLARE_PLUGIN(SND_2016_I1473343);
114
115
116}
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