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ARGUS_1988_I251097

Hyperon spectra in $e^+e^-$ collisions in the continuum at 10 GeV and at $\Upsilon_{1,2}$
Experiment: ARGUS (DORIS)
Inspire ID: 251097
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C39 (1988) 177, 1988
Beams: e- e+
Beam energies: (4.7, 4.7); (5.0, 5.0); (5.0, 5.0) GeV
Run details:
  • $e^+ e^-$ analysis near the $\Upsilon$ resonances

Measurement of the spectra for the production of $\Lambda$ and $\Xi^-$ baryons. Data are taken on the $\Upsilon(1S)$, $\Upsilon(2S)$ and in the nearby continuum. N.B. data tables 10 onwards are duplicates and therefore not implemented.

Source code: ARGUS_1988_I251097.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/UnstableParticles.hh"
  4
  5namespace Rivet {
  6
  7
  8  /// @brief hyperon production
  9  class ARGUS_1988_I251097 : public Analysis {
 10  public:
 11
 12    /// Constructor
 13    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1988_I251097);
 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(UnstableParticles(), "UFS");
 24
 25      for (unsigned int ix = 0; ix<2; ++ix) {
 26        for (unsigned int iy = 0; iy<7; ++iy) {
 27          book(_mult[ix][iy], ix+1, 1, iy+1);
 28        }
 29      }
 30      book(_hist_ups1_lambda , 3,1,1);
 31      book(_hist_ups2_lambda , 4,1,1);
 32      book(_hist_cont_lambda1, 5,1,1);
 33      book(_hist_cont_lambda2, 6,1,1);
 34
 35      book(_hist_ups1_xi     , 7,1,1);
 36      book(_hist_ups2_xi     , 8,1,1);
 37      book(_hist_cont_xi     , 9,1,1);
 38      book(_weightSum_cont,"TMP/sum_cont");
 39      book(_weightSum_Ups1,"TMP/sum_ups1");
 40      book(_weightSum_Ups2,"TMP/sum_ups2");
 41    }
 42
 43   /// Recursively walk the decay tree to find decay products of @a p
 44    void findDecayProducts(Particle mother, Particles& unstable) {
 45      for(const Particle & p: mother.children()) {
 46        const int id = abs(p.pid());
 47        if (id == 3122 || id == 3312 || id == 3212 || id == 3114 ||
 48                  id == 3224 || id == 3324 || id == 3334) {
 49          unstable.push_back(p);
 50        }
 51        if(!p.children().empty())
 52          findDecayProducts(p, unstable);
 53      }
 54    }
 55
 56    /// Perform the per-event analysis
 57    void analyze(const Event& event) {
 58      // First in unstable final state
 59      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
 60      Particles upsilons = ufs.particles(Cuts::pid==553 || Cuts::pid==100553);
 61      // continuum
 62      if (upsilons.empty()) {
 63        _weightSum_cont->fill();
 64        for (const Particle& p : ufs.particles()) {
 65          int id = p.abspid();
 66          double modp = p.p3().mod();
 67          double xp = 2.*modp/sqrtS();
 68          double xE = 2.*p.E()/sqrtS();
 69          double beta = modp/p.E();
 70          if (id == 3122) {
 71            _hist_cont_lambda1->fill(xp);
 72            _hist_cont_lambda2->fill(xE, 1./beta);
 73            _mult[1][0]->fill(Ecms);
 74          }
 75          else if (id == 3312) {
 76            _hist_cont_xi->fill(xE, 1./beta);
 77            _mult[1][1]->fill(Ecms);
 78          }
 79          else if (id == 3212) {
 80            _mult[1][2]->fill(Ecms);
 81          }
 82          else if (id == 3114) {
 83            _mult[1][3]->fill(Ecms);
 84          }
 85          else if (id == 3224) {
 86            _mult[1][4]->fill(Ecms);
 87          }
 88          else if (id == 3324) {
 89            _mult[1][5]->fill(Ecms);
 90          }
 91          else if (id == 3334) {
 92            _mult[1][6]->fill(Ecms);
 93          }
 94        }
 95      }
 96      // Upslion decays
 97      else {
 98        for (const Particle& ups : upsilons) {
 99          const int parentId = ups.pid();
100          if( parentId == 553)
101            _weightSum_Ups1->fill();
102          else
103            _weightSum_Ups2->fill();
104          Particles unstable;
105          // Find the decay products we want
106          findDecayProducts(ups,unstable);
107          LorentzTransform cms_boost;
108          if (ups.p3().mod() > 0.001)
109            cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
110          double mass = ups.mass();
111          for(const Particle & p : unstable) {
112            int id = p.abspid();
113            FourMomentum p2 = cms_boost.transform(p.momentum());
114            double modp = p2.p3().mod();
115            double xp = 2.*modp/mass;
116            if (id == 3122) {
117              if(parentId==553) {
118                _hist_ups1_lambda->fill(xp);
119                _mult[0][0]->fill(Ecms);
120              }
121              else {
122                _hist_ups2_lambda->fill(xp);
123              }
124            }
125            else if (id == 3312) {
126              if (parentId==553) {
127                _hist_ups1_xi->fill(xp);
128                _mult[0][1]->fill(Ecms);
129              }
130              else {
131                _hist_ups2_xi->fill(xp);
132              }
133            }
134            else if(parentId==553) {
135              if (id == 3212) {
136                _mult[0][2]->fill(Ecms);
137              }
138              else if (id == 3114) {
139                _mult[0][3]->fill(Ecms);
140              }
141              else if (id == 3224) {
142                _mult[0][4]->fill(Ecms);
143              }
144              else if (id == 3324) {
145                _mult[0][5]->fill(Ecms);
146              }
147              else if (id == 3334) {
148                _mult[0][6]->fill(Ecms);
149              }
150            }
151          }
152        }
153      }
154    }
155
156
157    /// Normalise histograms etc., after the run
158    void finalize() {
159      // multiplicities
160      const vector<CounterPtr> scales = {_weightSum_Ups1,_weightSum_cont};
161      for (unsigned int ix=0;ix<2;++ix) {
162        if (scales[ix]->effNumEntries()<=0.) continue;
163        scale(_mult[ix], 1./ *scales[ix]);
164      }
165      if(_weightSum_Ups1->val()>0.) {
166        scale(_hist_ups1_lambda,1./ *_weightSum_Ups1);
167        scale(_hist_ups1_xi    ,1./ *_weightSum_Ups1);
168      }
169      if(_weightSum_Ups2->val()>0.) {
170        scale(_hist_ups2_lambda,1./ *_weightSum_Ups2);
171        scale(_hist_ups2_xi    ,1./ *_weightSum_Ups2);
172      }
173      if(_weightSum_cont->val()) {
174        scale(_hist_cont_lambda1, 1./ *_weightSum_cont);
175        scale(_hist_cont_lambda2, 1./ *_weightSum_cont);
176        scale(_hist_cont_xi     , 1./ *_weightSum_cont);
177      }
178    }
179
180    /// @}
181
182
183    /// @name Histograms
184    /// @{
185    Histo1DPtr _hist_ups1_lambda, _hist_ups2_lambda, _hist_cont_lambda1, _hist_cont_lambda2;
186    Histo1DPtr _hist_ups1_xi, _hist_ups2_xi, _hist_cont_xi;
187    BinnedHistoPtr<int> _mult[2][7];
188    CounterPtr _weightSum_cont,_weightSum_Ups1,_weightSum_Ups2;
189    const int Ecms = 10;
190    /// @}
191
192
193  };
194
195
196  RIVET_DECLARE_PLUGIN(ARGUS_1988_I251097);
197
198
199}