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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	  std::ostringstream title;
 28	  title << "/TMP/MULT_" << ix << "_" << iy;
 29	  book(_mult[ix][iy],title.str());
 30	}
 31      }
 32      book(_hist_ups1_lambda , 3,1,1);
 33      book(_hist_ups2_lambda , 4,1,1);
 34      book(_hist_cont_lambda1, 5,1,1);
 35      book(_hist_cont_lambda2, 6,1,1);
 36           
 37      book(_hist_ups1_xi     , 7,1,1);
 38      book(_hist_ups2_xi     , 8,1,1);
 39      book(_hist_cont_xi     , 9,1,1);
 40      book(_weightSum_cont,"TMP/sum_cont");
 41      book(_weightSum_Ups1,"TMP/sum_ups1");
 42      book(_weightSum_Ups2,"TMP/sum_ups2");
 43    }
 44
 45   /// Recursively walk the decay tree to find decay products of @a p
 46    void findDecayProducts(Particle mother, Particles& unstable) {
 47      for(const Particle & p: mother.children()) {
 48        const int id = abs(p.pid());
 49	if (id == 3122 || id == 3312 || id == 3212 || id == 3114 ||
 50            id == 3224 || id == 3324 || id == 3334) {
 51	  unstable.push_back(p);
 52	}
 53	if(!p.children().empty())
 54	  findDecayProducts(p, unstable);
 55      }
 56    }
 57
 58    /// Perform the per-event analysis
 59    void analyze(const Event& event) {
 60      // First in unstable final state
 61      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
 62      Particles upsilons = ufs.particles(Cuts::pid==553 || Cuts::pid==100553);
 63      // continuum
 64      if (upsilons.empty()) { 
 65        _weightSum_cont->fill();
 66        for (const Particle& p : ufs.particles()) {
 67          int id = p.abspid();
 68	  double modp = p.p3().mod();
 69          double xp = 2.*modp/sqrtS();
 70          double xE = 2.*p.E()/sqrtS();
 71          double beta = modp/p.E();
 72          if (id == 3122) {
 73	    _hist_cont_lambda1->fill(xp);
 74	    _hist_cont_lambda2->fill(xE, 1./beta);
 75	    _mult[1][0]->fill();
 76          }
 77          else if (id == 3312) {
 78            _hist_cont_xi->fill(xE, 1./beta);
 79	    _mult[1][1]->fill();
 80          }
 81          else if (id == 3212) {
 82	    _mult[1][2]->fill();
 83          }
 84          else if (id == 3114) {
 85	    _mult[1][3]->fill();
 86          }
 87          else if (id == 3224) {
 88	    _mult[1][4]->fill();
 89          }
 90          else if (id == 3324) {
 91	    _mult[1][5]->fill();
 92          }
 93          else if (id == 3334) {
 94	    _mult[1][6]->fill();
 95          }
 96        }
 97      }
 98      // Upslion decays
 99      else {
100	for (const Particle& ups : upsilons) {
101	  const int parentId = ups.pid();
102	  if( parentId == 553)
103	    _weightSum_Ups1->fill();
104	  else
105	    _weightSum_Ups2->fill();
106	  Particles unstable;
107	  // Find the decay products we want
108	  findDecayProducts(ups,unstable);
109	  LorentzTransform cms_boost;
110	  if (ups.p3().mod() > 0.001)
111	    cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
112	  double mass = ups.mass();
113	  for(const Particle & p : unstable) {
114	    int id = p.abspid();
115	    FourMomentum p2 = cms_boost.transform(p.momentum());
116	    double modp = p2.p3().mod();
117	    double xp = 2.*modp/mass;
118	    if (id == 3122) {
119	      if(parentId==553) {
120		_hist_ups1_lambda->fill(xp);
121		_mult[0][0]->fill();
122	      }
123	      else {
124		_hist_ups2_lambda->fill(xp);
125	      }
126	    }
127	    else if (id == 3312) {
128	      if(parentId==553) {
129		_hist_ups1_xi->fill(xp);
130		_mult[0][1]->fill();
131	      }
132	      else {
133		_hist_ups2_xi->fill(xp);
134	      }
135	    }
136	    else if(parentId==553) {
137	      if (id == 3212) {
138		_mult[0][2]->fill();
139	      }
140	      else if (id == 3114) {
141		_mult[0][3]->fill();
142	      }
143	      else if (id == 3224) {
144		_mult[0][4]->fill();
145	      }
146	      else if (id == 3324) {
147		_mult[0][5]->fill();
148	      }
149	      else if (id == 3334) {
150		_mult[0][6]->fill();
151	      }
152	    }
153	  }
154	}
155      }
156    }
157
158
159    /// Normalise histograms etc., after the run
160    void finalize() {
161      // multiplicities
162      vector<CounterPtr> scales = {_weightSum_Ups1,_weightSum_cont};
163      for(unsigned int ix=0;ix<2;++ix) {
164	if(scales[ix]->effNumEntries()<=0.) continue;
165	for(unsigned int iy=0;iy<7;++iy) {
166	  Scatter2DPtr scatter;
167	  book(scatter, ix+1, 1, iy+1, true);
168	  scale(_mult[ix][iy],1./ *scales[ix]);
169	  scatter->point(0).setY(_mult[ix][iy]->val(),_mult[ix][iy]->err());
170	}
171      }
172      if(_weightSum_Ups1->val()>0.) {
173	scale(_hist_ups1_lambda,1./ *_weightSum_Ups1);
174	scale(_hist_ups1_xi    ,1./ *_weightSum_Ups1);
175      }
176      if(_weightSum_Ups2->val()>0.) {
177	scale(_hist_ups2_lambda,1./ *_weightSum_Ups2);
178	scale(_hist_ups2_xi    ,1./ *_weightSum_Ups2);
179      }
180      if(_weightSum_cont->val()) {
181	scale(_hist_cont_lambda1, 1./ *_weightSum_cont);
182	scale(_hist_cont_lambda2, 1./ *_weightSum_cont);
183	scale(_hist_cont_xi     , 1./ *_weightSum_cont);
184      }
185    }
186
187    //@}
188
189
190    /// @name Histograms
191    //@{
192    Histo1DPtr _hist_ups1_lambda, _hist_ups2_lambda, _hist_cont_lambda1, _hist_cont_lambda2;
193    Histo1DPtr _hist_ups1_xi, _hist_ups2_xi, _hist_cont_xi;
194    CounterPtr _mult[2][7];
195    CounterPtr _weightSum_cont,_weightSum_Ups1,_weightSum_Ups2;
196    //@}
197
198
199  };
200
201
202  // The hook for the plugin system
203  RIVET_DECLARE_PLUGIN(ARGUS_1988_I251097);
204
205
206}