rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

ARGUS_1989_I262551

Spectra for $\phi$ meson production for $e^+e^-$ collisions in the continuum at 10 GeV and at $\Upsilon_{1,2}$
Experiment: ARGUS (DORIS)
Inspire ID: 262551
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C41 (1989) 557, 1989
Beams: e- e+
Beam energies: (4.7, 4.7); (5.0, 5.0); (0.0, 0.0) GeV
Run details:
  • $e^+ e^-$ analysis near the $\Upsilon$ resonances

Measurement of the spectrum for $\phi$ mesons in the $e^+e^-$ continuum at 10 GeV and in $\Upsilon(1S)$ and $\Upsilon(2S)$ decays.

Source code: ARGUS_1989_I262551.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
133
134
135
136
137
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief phi spectrum in continuum, and Upsilon 1s and 2s decays
  class ARGUS_1989_I262551 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(ARGUS_1989_I262551);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(UnstableParticles(), "UFS");
      // Book histograms
      book(_h_cont, 1, 1, 1);
      book(_h_ups1, 2, 1, 1);
      book(_h_ups2, 2, 1, 2);
      book(_n_Phi[0], "/TMP/NUps1");
      book(_n_Phi[1], "/TMP/NUps2");
      book(_weightSum_cont, "TMP/weightSum_cont");
      book(_weightSum_Ups1, "TMP/weightSum_Ups1");
      book(_weightSum_Ups2, "TMP/weightSum_Ups2");
    }

    /// Recursively walk the decay tree to find decay products of @a p
    void findDecayProducts(Particle mother, Particles& phis) {
      for(const Particle & p: mother.children()) {
        const int id = p.pid();
	if(id == 333) {
	  phis.push_back(p);
	}
	if(!p.children().empty())
	  findDecayProducts(p, phis);
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Find the Upsilons among the unstables
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      Particles upsilons = ufs.particles(Cuts::pid==553 or Cuts::pid==100553);
      // Continuum
      if (upsilons.empty()) { 
        MSG_DEBUG("No Upsilons found => continuum event");
        _weightSum_cont->fill();
        for (const Particle& p : ufs.particles(Cuts::pid==333)) {
          const double xp = 2.*p.E()/sqrtS();
          const double beta = p.p3().mod() / p.E();
	  _h_cont->fill(xp,1./beta);
	}
      }
      // Upsilon(s) found
      else { 
        MSG_DEBUG("Upsilons found => resonance event");
        for (const Particle& ups : upsilons) {
          const int parentId = ups.pid();
	  if(parentId==553) {
	    _weightSum_Ups1->fill();
	  }
	  else {
	    _weightSum_Ups2->fill();
	  }
          Particles phis;
          // Find the decay products we want
          findDecayProducts(ups, phis);
          LorentzTransform cms_boost;
          if (ups.p3().mod() > 1*MeV)
            cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
          const double mass = ups.mass();
	  // loop over decay products
          for(const Particle& p : phis) {
            const FourMomentum p2 = cms_boost.transform(p.momentum());
            const double xp = 2.*p2.E()/mass;
            const double beta = p2.p3().mod()/p2.E();
	    if(parentId==553) {
	      _n_Phi[0]->fill();
	      _h_ups1->fill(xp,1./beta);
	    }
	    else {
	      _n_Phi[1]->fill();
	      _h_ups2->fill(xp,1./beta);
	    }
	  }
	}
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      if (_weightSum_cont->effNumEntries() > 0.)
	scale(_h_cont, sqr(sqrtS())*crossSection()/microbarn/sumOfWeights());
      if (_weightSum_Ups1->effNumEntries() > 0.) {
	scale(_h_ups1, 1./ *_weightSum_Ups1);
      }
      if (_weightSum_Ups2->effNumEntries() > 0.) {
	scale(_h_ups2, 1./ *_weightSum_Ups2);
      }
      // Counters
      vector<CounterPtr> scales = {_weightSum_Ups1,_weightSum_Ups2};
      for(unsigned int ix=0;ix<2;++ix) {
	Scatter2DPtr scatter;
	book(scatter, 3+ix, 1, 1, true);
	scale(_n_Phi[ix], 1./ *scales[ix]);
        scatter->point(0).setY(_n_Phi[ix]->val(),
			       _n_Phi[ix]->err());
      }
    }

    //@}


    /// @name Histograms
    //@{
    Histo1DPtr _h_cont, _h_ups1, _h_ups2;
    CounterPtr _n_Phi[2];
    CounterPtr _weightSum_cont,_weightSum_Ups1,_weightSum_Ups2;
    //@}


  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(ARGUS_1989_I262551);


}