Rivet analyses referenceSND_2003_I612867Cross section for $e^+e^-\to\pi\gamma$ for energies between 600 MeV and 970 MeVExperiment: SND (VEPP-2M) Inspire ID: 612867 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Cross section for $e^+e^-\to\pi\gamma$ for energies between 600 MeV and 970 MeV Source code: SND_2003_I612867.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4
5
6namespace Rivet {
7
8
9 /// @brief Add a short analysis description here
10 class SND_2003_I612867 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(SND_2003_I612867);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 declare(FinalState(), "FS");
23 book(_numPi0Gamma, "TMP/Pi0Gamma");
24 }
25
26
27 /// Perform the per-event analysis
28 void analyze(const Event& event) {
29
30 const FinalState& fs = apply<FinalState>(event, "FS");
31
32 map<long,int> nCount;
33 int ntotal(0);
34 for (const Particle& p : fs.particles()) {
35 nCount[p.pid()] += 1;
36 ++ntotal;
37 }
38 if(ntotal==2 && nCount[22]==1 && nCount[111]==1)
39 _numPi0Gamma->fill();
40
41 }
42
43
44 /// Normalise histograms etc., after the run
45 void finalize() {
46
47 double sigma = _numPi0Gamma->val();
48 double error = _numPi0Gamma->err();
49 sigma *= crossSection()/ sumOfWeights() /nanobarn;
50 error *= crossSection()/ sumOfWeights() /nanobarn;
51 Estimate1DPtr mult;
52 book(mult, 1, 1, 1);
53 for (auto& b : mult->bins()) {
54 if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
55 b.set(sigma, error);
56 }
57 }
58 }
59
60 /// @}
61
62
63 /// @name Histograms
64 /// @{
65 CounterPtr _numPi0Gamma;
66 /// @}
67
68
69 };
70
71
72 RIVET_DECLARE_PLUGIN(SND_2003_I612867);
73
74
75}
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