rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

ARGUS_1991_I315059

$D^0$, $D^+$, $D^{*+}$ production in $e^+e^-$ annihilation at 10.47 GeV, and $B$ decays
Experiment: ARGUS (DORIS)
Inspire ID: 315059
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C52 (1991) 353-360, 1991
Beams: e- e+
Beam energies: ANY
Run details:
  • e+e- to hadrons, at 10.58 GeV, or Upsilon(4S)

Measurement of the scaled momentum spectra for $D^0$, $D^+$, $D^{*+}$ production in $e^+e^-$ annihilation at 10.47 GeV, and from $B$ decays at the $\Upsilon(4S)$.

Source code: ARGUS_1991_I315059.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/Beam.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// @brief ARGUS D0, D+, D*+ production
 10  class ARGUS_1991_I315059 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1991_I315059);
 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(UnstableParticles(), "UFS");
 25      declare(Beam(), "Beams");
 26
 27      // Book histograms
 28      book(_n_D0   , 1,1,1);
 29      book(_n_Dp   , 1,1,2);
 30      book(_n_DStar, 1,1,3);
 31
 32      book(_h_x_D0   , 2,1,1);
 33      book(_h_x_Dp   , 3,1,1);
 34      book(_h_x_DStar, 4,1,1);
 35
 36      book(_h_p_D0   , 5,1,1);
 37      book(_h_p_Dp   , 6,1,1);
 38      book(_h_p_DStar, 7,1,1);
 39
 40      book(_c_cont, "/TMP/c_cont");
 41      book(_c_ups , "/TMP/c_ups");
 42    }
 43
 44
 45    /// Perform the per-event analysis
 46    void analyze(const Event& event) {
 47      // Get beams and average beam momentum
 48      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
 49      const double meanBeamMom = ( beams.first.p3().mod() +
 50                                   beams.second.p3().mod() ) / 2.0;
 51      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
 52      // Find the Upsilon(4S) among the unstables
 53      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
 54      Particles upsilons = ufs.particles(Cuts::pid==300553);
 55      // Continuum
 56      if (upsilons.empty()) {
 57	_c_cont->fill();
 58        MSG_DEBUG("No Upsilons found => continuum event");
 59	for(const Particle &p : ufs.particles(Cuts::abspid==411 or Cuts::abspid==421 or Cuts::abspid==413)) {
 60	  double xp = p.p3().mod()/sqrt(sqr(meanBeamMom)+sqr(p.mass()));
 61	  if(p.abspid()==421) {
 62	    _h_x_D0->fill(xp);
 63	    _n_D0->fill(10.6);
 64	  }
 65	  else if(p.abspid()==411) {
 66	    _h_x_Dp->fill(xp);
 67	    _n_Dp->fill(10.6);
 68	  }
 69	  else if(p.abspid()==413) {
 70	    _h_x_DStar->fill(xp);
 71	    _n_DStar->fill(10.6);
 72	  }
 73	}
 74      }
 75      // upsilon decay
 76      else {
 77        for (const Particle& ups : upsilons) {
 78	  _c_ups->fill();
 79          Particles unstable;
 80          // Find the decay products we want
 81          findDecayProducts(ups, unstable);
 82	  // boost to rest frame (if required)
 83          LorentzTransform cms_boost;
 84          if (ups.p3().mod() > 1*MeV)
 85            cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
 86          for(const Particle& p : unstable) {
 87            const FourMomentum p2 = cms_boost.transform(p.momentum());
 88	    double modp = p2.p3().mod();
 89	    if(p.abspid()==421) {
 90	      _h_p_D0->fill(modp);
 91	    }
 92	    else if(p.abspid()==411) {
 93	      _h_p_Dp->fill(modp);
 94	    }
 95	    else if(p.abspid()==413) {
 96	      _h_p_DStar->fill(modp);
 97	    }
 98	  }
 99	}
100      }
101    }
102
103    /// Recursively walk the decay tree to find decay products of @a p
104    void findDecayProducts(Particle mother, Particles& unstable) {
105      for(const Particle & p: mother.children()) {
106        const int id = p.abspid();
107	if (id == 411 || id == 421) {
108	  unstable.push_back(p);
109	}
110	else if (id == 413 ) {
111	  unstable.push_back(p);
112	  findDecayProducts(p, unstable);
113	}
114	else if(!p.children().empty())
115	  findDecayProducts(p, unstable);
116      }
117    }
118
119    /// Normalise histograms etc., after the run
120    void finalize() {
121      // brs for the decays used (PDG 2018)
122      double brD0 = 0.0389;
123      double brDp = 0.0898;
124      double brDStar = 0.677;
125      if(_c_cont->numEntries()!=0) {
126	scale(_n_D0      , 1./sumOfWeights()*crossSection()/nanobarn);
127	scale(_n_Dp      , 1./sumOfWeights()*crossSection()/nanobarn);
128	scale(_n_DStar  ,  1./sumOfWeights()*crossSection()/nanobarn);
129	scale(_h_x_D0   , brD0/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
130	scale(_h_x_Dp   , brDp/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
131	scale(_h_x_DStar, brD0*brDStar/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
132      }
133      if(_c_ups->numEntries()!=0) {
134	scale(_h_p_D0   , 1e3*0.5*brD0/ *_c_ups);
135	scale(_h_p_Dp   , 1e3*0.5*brDp/ *_c_ups);
136	scale(_h_p_DStar, 1e3*0.5*brD0*brDStar/ *_c_ups);
137      }
138    }
139
140    //@}
141
142
143    /// @name Histograms
144    //@{
145    Histo1DPtr _n_D0,_n_Dp,_n_DStar;
146    Histo1DPtr _h_x_D0,_h_x_Dp,_h_x_DStar;
147    Histo1DPtr _h_p_D0,_h_p_Dp,_h_p_DStar;
148    CounterPtr _c_cont, _c_ups;
149    //@}
150
151
152  };
153
154
155  // The hook for the plugin system
156  RIVET_DECLARE_PLUGIN(ARGUS_1991_I315059);
157
158
159}