Rivet Analyses Reference

PLUTO_1981_I156315

Energy-Energy correlation for a range of energies between 7.7 and 31.6 GeV
Experiment: PLUTO (DORIS/Petra)
Inspire ID: 156315
Status: VALIDATED
Authors:
  • Peter Richardson
No references listed
Beams: e+ e-
Beam energies: (3.9, 3.9); (4.7, 4.7); (6.0, 6.0); (6.5, 6.5); (8.5, 8.5); (11.0, 11.0); (13.8, 13.8); (15.4, 15.4) GeV
Run details:
  • e+e- to hadrons at 7.7,9.4,12.,13.,17.,22.,27.6,30.8 GeV CMS Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.

Measurement of the energy-energy correlation, and its assymetry, or a range of energies between 7.7 and 31.6 GeV. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.

Source code: PLUTO_1981_I156315.cc
  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
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FinalState.hh"

namespace Rivet {


  /// @brief EEC for a wide range of energies
  class PLUTO_1981_I156315 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(PLUTO_1981_I156315);


    /// @name Analysis methods
    //@{

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

      // Initialise and register projections
      declare(FinalState(), "FS");
      // Book histograms
      unsigned int iloc(0);
      if(isCompatibleWithSqrtS(7.7)) {
        iloc=1;
      }
      else if(isCompatibleWithSqrtS(9.4)) {
        iloc=2;
      }
      else if (isCompatibleWithSqrtS(12.)) {
        iloc=3;
      }
      else if (isCompatibleWithSqrtS(13.)) {
        iloc=4;
      }
      else if (isCompatibleWithSqrtS(17.)) {
        iloc=5;
      }
      else if (isCompatibleWithSqrtS(22.)) {
        iloc=6;
      }
      else if (isCompatibleWithSqrtS(27.6)) {
        iloc=7;
      }
      else if (isCompatibleWithSqrtS(30,31.6)) {
        iloc=8;
      }
      else
	MSG_ERROR("Beam energy not supported!");
      // Book histograms
      book(_h_EEC, 1, 1, iloc);
      if(iloc==7||iloc==8) {
	book(_h_AEEC, 5, 1, 1);
	// _h_opposite = bookHisto1D(2, 1, 1);
      }
      else if(iloc==21 ||iloc==2)
	book(_h_AEEC,4, 1, 1);
      book(_weightSum,"TMP/weightSum");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // First, veto on leptonic events by requiring at least 4 charged FS particles
      const FinalState& fs = apply<FinalState>(event, "FS");
      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
      if ( fs.particles().size() < 2) {
        MSG_DEBUG("Failed leptonic event cut");
        vetoEvent;
      }
      MSG_DEBUG("Passed leptonic event cut");
      _weightSum->fill();

      double Evis = 0.0;
      for (const Particle& p : fs.particles()) {
        Evis += p.E();
      }
      double Evis2 = sqr(Evis);
      // (A)EEC
      // Need iterators since second loop starts at current outer loop iterator, i.e. no "foreach" here!
      for (Particles::const_iterator p_i = fs.particles().begin(); p_i != fs.particles().end(); ++p_i) {
        for (Particles::const_iterator p_j = p_i; p_j != fs.particles().end(); ++p_j) {
          const Vector3 mom3_i = p_i->momentum().p3();
          const Vector3 mom3_j = p_j->momentum().p3();
          const double energy_i = p_i->momentum().E();
          const double energy_j = p_j->momentum().E();
          const double thetaij = mom3_i.unit().angle(mom3_j.unit())/M_PI*180.;
          double eec = (energy_i*energy_j) / Evis2;
	  if(p_i != p_j) eec *= 2.;
	  _h_EEC ->fill(thetaij,  eec);
	  // if(_h_opposite) _h_opposite ->fill(mom3_i.unit().dot(mom3_j.unit()),  eec);
	  if(_h_AEEC) {
	    if (thetaij < 90.) {
	      _h_AEEC->fill(thetaij, -eec);
	    }
	    else {
	      _h_AEEC  ->fill(180.-thetaij, eec);
	    }
	  }
        }
      }

    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_EEC , 360.0/M_PI/ *_weightSum);
      scale(_h_AEEC, 360.0/M_PI/ *_weightSum);
      // scale(_h_opposite, 2./ *_weightSum);

    }

    //@}

    /// @name Histograms
    //@{
    Histo1DPtr _h_EEC, _h_AEEC, _h_opposite;
    CounterPtr _weightSum;
    //@}

  };


  // The hook for the plugin system
  RIVET_DECLARE_PLUGIN(PLUTO_1981_I156315);


}