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BESII_2007_I762901

Cross sections for light hadrons at 3.650 and 3.773 GeV
Experiment: BESII (BEPC)
Inspire ID: 762901
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B656 (2007) 30-37, 2007
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Cross section for $e^+e^-\to 2\pi^+2\pi^-K^+K^-$, $\pi^+\pi^-2K^+2K^-$, $2\pi^+2\pi^-p\bar{p}$, $3\pi^+3\pi^-$, $2\pi^+2\pi^-K^+K^-\pi^0$, $\rho^0\pi^+\pi^-$, $\rho^0K^+K^-$, $\rho^0p\bar{p}$, $K^{*0}K^-\pi^++\text{c.c.}$ at 3.650 and 3.773 GeV.

Source code: BESII_2007_I762901.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// @brief Add a short analysis description here
 10  class BESII_2007_I762901 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2007_I762901);
 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(FinalState(), "FS");
 25      declare(UnstableParticles(), "UFS");
 26
 27      // Book histograms
 28      for(unsigned int ix=1;ix<11;++ix) {
 29	stringstream ss;
 30	ss << "TMP/n" << ix;
 31	book(_nMeson[ix], ss.str());
 32      }
 33
 34    }
 35
 36    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 37      for(const Particle &child : p.children()) {
 38	if(child.children().empty()) {
 39	  nRes[child.pid()]-=1;
 40	  --ncount;
 41	}
 42	else
 43	  findChildren(child,nRes,ncount);
 44      }
 45    }
 46
 47    /// Perform the per-event analysis
 48    void analyze(const Event& event) {
 49      const FinalState& fs = apply<FinalState>(event, "FS");
 50
 51      map<long,int> nCount;
 52      int ntotal(0);
 53      for (const Particle& p : fs.particles()) {
 54	nCount[p.pid()] += 1;
 55	++ntotal;
 56      }
 57      if(ntotal==6) {
 58	if(nCount[211]==2 && nCount[-211]==2 && nCount[321]==1 && nCount[-321]==1)
 59	  _nMeson[1]->fill();
 60	else if(nCount[211]==1 && nCount[-211]==1 && nCount[321]==2 && nCount[-321]==2)
 61	  _nMeson[2]->fill();
 62	else if(nCount[211]==2 && nCount[-211]==2 && nCount[2212]==1 && nCount[-2212]==1)
 63	  _nMeson[3]->fill();
 64	else if(nCount[211]==3 && nCount[-211]==3)
 65	  _nMeson[4]->fill();
 66      }
 67      else if(ntotal==7) {
 68	if(nCount[211]==2 && nCount[-211]==2 && nCount[321]==1 && nCount[-321]==1 && nCount[111]==1)
 69	  _nMeson[5]->fill();
 70      }
 71      const FinalState& ufs = apply<FinalState>(event, "UFS");
 72      for (const Particle& p : ufs.particles()) {
 73       	if(p.children().empty()) continue;
 74       	if(p.pid()!=113 && abs(p.pid())!=313) continue;
 75     	map<long,int> nRes = nCount;
 76     	int ncount = ntotal;
 77     	findChildren(p,nRes,ncount);
 78      	if(p.pid()==113) {
 79       	  if(ncount!=2) continue;
 80      	  unsigned int nPi(0),nK(0),nProt(0);
 81       	  bool matched = true;
 82       	  for(auto const & val : nRes) {
 83       	    if(abs(val.first)==211 && val.second==1) {
 84       	      nPi+=1;
 85       	    }
 86       	    else if(abs(val.first)==321 && val.second==1) {
 87       	      nK+=1;
 88       	    }
 89       	    else if(abs(val.first)==2212 && val.second==1) {
 90       	      nProt+=1;
 91       	    }
 92       	    else if(val.second!=0) {
 93       	      matched = false;
 94       	      break;
 95       	    }
 96       	  }
 97       	  if(matched) {
 98       	    if(nProt==2 && nPi==0 && nK==0)
 99       	      _nMeson[9]->fill();
100       	    else if(nProt==0 && nPi==2 && nK==0)
101       	      _nMeson[7]->fill();
102       	    else if(nProt==0 && nPi==0 && nK==2)
103       	      _nMeson[8]->fill();
104       	  }
105       	}
106     	else if(abs(p.pid())==313) {
107       	  if(ncount!=2) continue;
108      	  unsigned int npi(0),nK(0);
109      	  bool matched = true;
110      	  int ipi = p.pid()==313 ?  211 : -211;
111       	  int iK  = p.pid()==313 ? -321 :  321;
112      	  for(auto const & val : nRes) {
113      	    if(abs(val.first)== ipi && val.second==1) {
114      	      npi+=1;
115      	    }
116      	    else if(abs(val.first)==iK && val.second==1) {
117      	      nK+=1;
118      	    }
119       	    else if(val.second!=0) {
120       	      matched = false;
121       	      break;
122       	    }
123       	  }
124       	  if(matched) {
125       	    if(npi==1&&nK==1)
126       	      _nMeson[10]->fill();
127       	  }
128       	}
129      }
130    }
131
132
133    /// Normalise histograms etc., after the run
134    void finalize() {
135      for(unsigned int ix=1;ix<11;++ix) {
136	if(ix==6) continue;
137	double sigma = _nMeson[ix]->val();
138	double error = _nMeson[ix]->err();
139    	sigma *= crossSection()/ sumOfWeights() /picobarn;
140    	error *= crossSection()/ sumOfWeights() /picobarn;
141	Scatter2D temphisto(refData(1, 1, ix));
142	Scatter2DPtr  mult;
143        book(mult, 1, 1, ix);
144	for (size_t b = 0; b < temphisto.numPoints(); b++) {
145	  const double x  = temphisto.point(b).x();
146	  pair<double,double> ex = temphisto.point(b).xErrs();
147	  pair<double,double> ex2 = ex;
148	  if(ex2.first ==0.) ex2. first=0.0001;
149	  if(ex2.second==0.) ex2.second=0.0001;
150	  if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
151	    mult->addPoint(x, sigma, ex, make_pair(error,error));
152	  }
153	  else {
154	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
155	  }
156	}
157      }
158    }
159
160    //@}
161
162
163    /// @name Histograms
164    //@{
165    CounterPtr _nMeson[11];
166    //@}
167
168
169  };
170
171
172  // The hook for the plugin system
173  RIVET_DECLARE_PLUGIN(BESII_2007_I762901);
174
175
176}