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CMD2_2000_I523691

Cross section for $e^+e^-\to \pi^+\pi^-\pi^0$ near the $\omega$ mass
Experiment: CMD2 (VEPP-2M)
Inspire ID: 523691
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B434 (1998) 426-436, 1998
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+ e- to hadrons

Measurement of the cross section for $e^+e^-\to \pi^+\pi^-\pi^0$ for energies near the $\omega$ mass.

Source code: CMD2_2000_I523691.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 CMD2_2000_I523691 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_2000_I523691);
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
26      book(_num3pi, "TMP/num3");
27    }
28
29
30    /// Perform the per-event analysis
31    void analyze(const Event& event) {
32      const FinalState& fs = apply<FinalState>(event, "FS");
33
34      map<long,int> nCount;
35      int ntotal(0);
36      for (const Particle& p : fs.particles()) {
37	nCount[p.pid()] += 1;
38	++ntotal;
39      }
40      if(ntotal!=3) vetoEvent;
41      if(nCount[-211]==1&&nCount[211]==1&&nCount[111]==1)
42	_num3pi->fill();
43    }
44
45
46    /// Normalise histograms etc., after the run
47    void finalize() {
48      double sigma = _num3pi->val();
49      double error = _num3pi->err();
50      sigma *= crossSection()/ sumOfWeights() /nanobarn;
51      error *= crossSection()/ sumOfWeights() /nanobarn;
52      Estimate1DPtr mult;
53      book(mult, 1, 1, 1);
54      for (auto& b : mult->bins()) {
55        if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
56          b.set(sigma, error);
57        }
58      }
59    }
60
61    /// @}
62
63
64    /// @name Histograms
65    /// @{
66    CounterPtr _num3pi;
67    /// @}
68
69
70  };
71
72
73  RIVET_DECLARE_PLUGIN(CMD2_2000_I523691);
74
75
76}