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BABAR_2008_I765258

Cross Section for $e^+e^-\to$ $K^+K^-\eta$, $K^+K^-\pi^0$ and $K^0_SK^\pm\pi^\mp$ from threshold to 4.6 GeV
Experiment: BABAR (PEP-II)
Inspire ID: 765258
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Rev. D77 (2008) 092002, 2008
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Measurement of the cross section for $e^+e^-\to$ $K^+K^-\eta$, $K^+K^-\pi^0$ and $K^0_SK^\pm\pi^\mp$ via radiative return, including the identification of $\phi$ and $\eta$ mesons for energies from threshold to 4.6 GeV.

Source code: BABAR_2008_I765258.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 BABAR_2008_I765258 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2008_I765258);
 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<6;++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      const FinalState& ufs = apply<FinalState>(event, "UFS");
 58      for (const Particle& p : ufs.particles(Cuts::pid==221 or Cuts::pid==333)) {
 59        if(p.children().empty()) continue;
 60        map<long,int> nRes = nCount;
 61        int ncount = ntotal;
 62        findChildren(p,nRes,ncount);
 63
 64        if(p.pid()==221) {
 65          bool matchedKK = false;
 66          if(ncount==2) {
 67            matchedKK = true;
 68            for(auto const & val : nRes) {
 69              if(abs(val.first)==321) {
 70                if(val.second!=1) {
 71                  matchedKK = false;
 72                  break;
 73                }
 74              }
 75              else if(val.second!=0) {
 76                matchedKK = false;
 77                break;
 78              }
 79            }
 80          }
 81          if(matchedKK) _nMeson[4]->fill();
 82          for (const Particle& p2 : ufs.particles()) {
 83            if(p2.pid()!=333) continue;
 84            if(p2.parents()[0].isSame(p)) continue;
 85            map<long,int> nResB = nRes;
 86            int ncountB = ncount;
 87            findChildren(p2,nResB,ncountB);
 88            if(ncountB!=0) continue;
 89            bool matched2 = true;
 90            for(auto const & val : nResB) {
 91              if(val.second!=0) {
 92                matched2 = false;
 93                break;
 94              }
 95            }
 96            if(matched2) {
 97              _nMeson[5]->fill();
 98              break;
 99            }
100          }
101        }
102        else if(p.pid()==333) {
103          if(ncount!=1) continue;
104          bool matched = true;
105          for(auto const & val : nRes) {
106            if(val.first==111) {
107              if(val.second!=1) {
108                matched = false;
109                break;
110              }
111            }
112            else if(val.second!=0) {
113              matched = false;
114              break;
115            }
116          }
117          if(matched)
118            _nMeson[3]->fill();
119        }
120      }
121
122
123      if(ntotal==3 && nCount[310]==1 &&
124         ((nCount[ 211]==1&&nCount[-321]==1)||
125          (nCount[-211]==1&&nCount[ 321]==1)))
126        _nMeson[1]->fill();
127      else if(ntotal==3 && nCount[321]==1 &&
128              nCount[-321]==1 && nCount[111]==1)
129        _nMeson[2]->fill();
130    }
131
132
133    /// Normalise histograms etc., after the run
134    void finalize() {
135      for(unsigned int ix=1;ix<6;++ix) {
136        double sigma = _nMeson[ix]->val();
137        double error = _nMeson[ix]->err();
138        sigma *= crossSection()/ sumOfWeights() /nanobarn;
139        error *= crossSection()/ sumOfWeights() /nanobarn;
140        Estimate1DPtr  mult;
141        book(mult, ix, 1, 1);
142        for (auto& b : mult->bins()) {
143          if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
144            b.set(sigma, error);
145          }
146        }
147      }
148    }
149
150    /// @}
151
152
153    /// @name Histograms
154    /// @{
155    CounterPtr _nMeson[6];
156    /// @}
157
158
159  };
160
161
162  RIVET_DECLARE_PLUGIN(BABAR_2008_I765258);
163
164}