Rivet Analyses Reference

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/Beam.hh"

namespace Rivet {


  /// @brief CLEO e+e- > e+e- pi0,eta,eta'
  class CLEOII_1997_I446031 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1997_I446031);


    /// @name Analysis methods
    ///@{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(Beam(), "Beams");
      declare(FinalState(),"FS");
      declare(UnstableParticles(), "UFS");

      // book the histograms
      book(_h_pi0,1,1,1);
      for (unsigned int ix=0; ix<3; ++ix) book(_h_eta [ix],ix+2,1,1);
      for (unsigned int ix=0; ix<6; ++ix) book(_h_etap[ix],ix+5,1,1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // find scattered leptons and calc Q2
      const Beam& beams = apply<Beam>(event, "Beams");
      double q12 = -1, q22 = -1;
      if (!findScattered(beams.beams().first,  q12)) vetoEvent;
      if (!findScattered(beams.beams().second, q22)) vetoEvent;
      double scale = max(q12,q22);
      // check the final state
      const FinalState & fs = apply<FinalState>(event, "FS");
      map<long,int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
        nCount[p.pid()] += 1;
        ++ntotal;
      }
      // find the meson
      const FinalState& ufs = apply<FinalState>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::pid==111 or
                                             Cuts::pid==221 or
                                             Cuts::pid==331)) {
        if(p.children().empty()) continue;
        map<long,int> nRes = nCount;
        int ncount = ntotal;
        findChildren(p,nRes,ncount);
        bool matched = true;
        for(auto const & val : nRes) {
          if(abs(val.first)==11) {
            if(val.second!=1) {
              matched = false;
              break;
            }
          }
          else if(val.second!=0) {
            matched = false;
            break;
          }
        }
        if (matched) {
          if (p.pid()==111) {
            _h_pi0->fill(scale);
          } else if (p.pid()==221) {
            for (unsigned int ix=0; ix<3; ++ix)
              _h_eta[ix]->fill(scale);
          } else if(p.pid()==331) {
            for (unsigned int ix=0; ix<6; ++ix)
              _h_etap[ix]->fill(scale);
          }
          break;
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // normalize the cross sections
      scale(_h_pi0, crossSection()/femtobarn/sumW());
      for(unsigned int ix=0;ix<3;++ix)
        scale(_h_eta[ix], crossSection()/femtobarn/sumW());
      for(unsigned int ix=0;ix<6;++ix)
        scale(_h_etap[ix], crossSection()/femtobarn/sumW());
    }

    ///@}


    /// @name Helpers
    /// @{

    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
      for (const Particle &child : p.children()) {
        if (child.children().empty()) {
          --nRes[child.pid()];
          --ncount;
        } else {
          findChildren(child,nRes,ncount);
        }
      }
    }


    bool findScattered(Particle beam, double& q2) {
      bool found = false;
      Particle scat = beam;
      while (!scat.children().empty()) {
        found = false;
        for (const Particle & p : scat.children()) {
          if (p.pid()==scat.pid()) {
            scat=p;
            found=true;
            break;
          }
        }
        if (!found) break;
      }
      if (!found) return false;
      q2 = -(beam.momentum() - scat.momentum()).mass2();
      return true;
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_pi0,_h_eta[3],_h_etap[6];
    /// @}

  };


  RIVET_DECLARE_PLUGIN(CLEOII_1997_I446031);

}