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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      
 59      for (const Particle& p : ufs.particles(Cuts::pid==221 or Cuts::pid==333)) {
 60	if(p.children().empty()) continue;
 61	map<long,int> nRes = nCount;
 62	int ncount = ntotal;
 63	findChildren(p,nRes,ncount);
 64	  
 65	if(p.pid()==221) {
 66	  bool matchedKK = false;
 67	  if(ncount==2) {
 68	    matchedKK = true;
 69	    for(auto const & val : nRes) {
 70	      if(abs(val.first)==321) {
 71		if(val.second!=1) {
 72		  matchedKK = false;
 73		  break;
 74		}
 75	      }
 76	      else if(val.second!=0) {
 77		matchedKK = false;
 78		break;
 79	      }
 80	    }
 81	  }
 82	  if(matchedKK) _nMeson[4]->fill();
 83	  for (const Particle& p2 : ufs.particles()) {
 84	    if(p2.pid()!=333) continue;
 85	    if(p2.parents()[0].isSame(p)) continue;
 86	    map<long,int> nResB = nRes;
 87	    int ncountB = ncount;
 88	    findChildren(p2,nResB,ncountB);
 89	    if(ncountB!=0) continue;
 90	    bool matched2 = true;
 91	    for(auto const & val : nResB) {
 92	      if(val.second!=0) {
 93		matched2 = false;
 94		break;
 95	      }
 96	    }
 97	    if(matched2) {
 98	      _nMeson[5]->fill();
 99	      break;
100	    }
101	  }
102	}
103	else if(p.pid()==333) {
104	  if(ncount!=1) continue;
105	  bool matched = true;
106	  for(auto const & val : nRes) {
107	    if(val.first==111) {
108	      if(val.second!=1) {
109		matched = false;
110		break;
111	      }
112	    }
113	    else if(val.second!=0) {
114	      matched = false;
115	      break;
116	    }
117	  }
118	  if(matched)
119	    _nMeson[3]->fill();
120	}
121      }
122
123
124      if(ntotal==3 && nCount[310]==1 &&
125	 ((nCount[ 211]==1&&nCount[-321]==1)||
126	  (nCount[-211]==1&&nCount[ 321]==1)))
127	 _nMeson[1]->fill();
128      else if(ntotal==3 && nCount[321]==1 &&
129	      nCount[-321]==1 && nCount[111]==1)
130	 _nMeson[2]->fill();
131    }
132
133
134    /// Normalise histograms etc., after the run
135    void finalize() {
136      for(unsigned int ix=1;ix<6;++ix) {
137	double sigma = _nMeson[ix]->val();
138	double error = _nMeson[ix]->err();
139    	sigma *= crossSection()/ sumOfWeights() /nanobarn;
140    	error *= crossSection()/ sumOfWeights() /nanobarn; 
141	Scatter2D temphisto(refData(ix, 1, 1));
142    	Scatter2DPtr  mult;
143        book(mult, ix, 1, 1);
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[6];
166    //@}
167
168
169  };
170
171
172  // The hook for the plugin system
173  RIVET_DECLARE_PLUGIN(BABAR_2008_I765258);
174
175
176}