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BESII_2008_I801210

Cross-sections for light hadrons at 3.773, 3.650 and 3.6648 GeV
Experiment: BESII (BEPC II)
Inspire ID: 801210
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B670 (2008) 184-189, 2008
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Cross section for $e^+e^-\to \pi^+\pi^-$, $K^+K^-$, $2\pi^+2\pi^-$, $K^+K^-\pi^+\pi^-$ and $3\pi^+3\pi^-$ together with a $\pi^0\pi^0$ pair at 3.773, 3.650 and 3.6648 GeV.

Source code: BESII_2008_I801210.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Cross-sections for light hadrons at 3.773, 3.650 and 3.6648 GeV
 9  class BESII_2008_I801210 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2008_I801210);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21
22      // Initialise and register projections
23      declare(FinalState(), "FS");
24
25      // Book histograms
26      for(unsigned int ix=1;ix<6;++ix) {
27        stringstream ss;
28        ss << "TMP/n" << ix;
29        book(_nMeson[ix], ss.str());
30      }
31    }
32
33
34    /// Perform the per-event analysis
35    void analyze(const Event& event) {
36      const FinalState& fs = apply<FinalState>(event, "FS");
37
38      map<long,int> nCount;
39      int ntotal(0);
40      for (const Particle& p : fs.particles()) {
41        nCount[p.pid()] += 1;
42        ++ntotal;
43      }
44      if(nCount[111]!=2) vetoEvent;
45
46      if(ntotal==4) {
47        if(nCount[211]==1 && nCount[-211]==1)
48          _nMeson[1]->fill();
49        else if(nCount[321]==1 && nCount[-321]==1)
50          _nMeson[2]->fill();
51      }
52      else if(ntotal==6) {
53        if(nCount[211]==2 && nCount[-211]==2)
54          _nMeson[3]->fill();
55        else if(nCount[321]==1 && nCount[-321]==1 &&
56                nCount[211]==1 && nCount[-211]==1)
57          _nMeson[4]->fill();
58      }
59      else if(ntotal==8) {
60        if(nCount[211]==3 && nCount[-211]==3)
61          _nMeson[5]->fill();
62      }
63
64    }
65
66
67    /// Normalise histograms etc., after the run
68    void finalize() {
69      for(unsigned int ix=1;ix<6;++ix) {
70        double sigma = _nMeson[ix]->val();
71        double error = _nMeson[ix]->err();
72        sigma *= crossSection()/ sumOfWeights() /picobarn;
73        error *= crossSection()/ sumOfWeights() /picobarn;
74        Estimate1DPtr  mult;
75        book(mult, 1, 1, ix);
76        for (auto& b : mult->bins()) {
77          if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
78            b.set(sigma, error);
79          }
80        }
81      }
82    }
83
84    /// @}
85
86
87    /// @name Histograms
88    /// @{
89    CounterPtr _nMeson[6];
90    /// @}
91
92
93  };
94
95
96
97  RIVET_DECLARE_PLUGIN(BESII_2008_I801210);
98
99}