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BESII_2008_I801210

Cross sections for light hadrons at 3.773, 3.650 and 3.6648 GeV
Experiment: BESII (BEPC II)
Inspire ID: 801210
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B670 (2008) 184-189, 2008
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Cross section for $e^+e^-\to \pi^+\pi^-$, $K^+K^-$, $2\pi^+2\pi^-$, $K^+K^-\pi^+\pi^-$ and $3\pi^+3\pi^-$ together with a $\pi^0\pi^0$ pair at 3.773, 3.650 and 3.6648 GeV.

Source code: BESII_2008_I801210.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4
  5namespace Rivet {
  6
  7
  8  /// @brief Add a short analysis description here
  9  class BESII_2008_I801210 : public Analysis {
 10  public:
 11
 12    /// Constructor
 13    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2008_I801210);
 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(FinalState(), "FS");
 24
 25      // Book histograms
 26      for(unsigned int ix=1;ix<6;++ix) {
 27	stringstream ss;
 28	ss << "TMP/n" << ix;
 29	book(_nMeson[ix], ss.str());
 30      }
 31    }
 32
 33
 34    /// Perform the per-event analysis
 35    void analyze(const Event& event) {
 36      const FinalState& fs = apply<FinalState>(event, "FS");
 37
 38      map<long,int> nCount;
 39      int ntotal(0);
 40      for (const Particle& p : fs.particles()) {
 41	nCount[p.pid()] += 1;
 42	++ntotal;
 43      }
 44      if(nCount[111]!=2) vetoEvent;
 45
 46      if(ntotal==4) {
 47	if(nCount[211]==1 && nCount[-211]==1)
 48	  _nMeson[1]->fill();
 49	else if(nCount[321]==1 && nCount[-321]==1)
 50	  _nMeson[2]->fill();
 51      }
 52      else if(ntotal==6) {
 53	if(nCount[211]==2 && nCount[-211]==2)
 54	  _nMeson[3]->fill();
 55	else if(nCount[321]==1 && nCount[-321]==1 &&
 56		nCount[211]==1 && nCount[-211]==1)
 57	  _nMeson[4]->fill();
 58      }
 59      else if(ntotal==8) {
 60	if(nCount[211]==3 && nCount[-211]==3)
 61	  _nMeson[5]->fill();
 62      }
 63      
 64    }
 65
 66
 67    /// Normalise histograms etc., after the run
 68    void finalize() {
 69      for(unsigned int ix=1;ix<6;++ix) {
 70	double sigma = _nMeson[ix]->val();
 71	double error = _nMeson[ix]->err();
 72    	sigma *= crossSection()/ sumOfWeights() /picobarn;
 73    	error *= crossSection()/ sumOfWeights() /picobarn; 
 74	Scatter2D temphisto(refData(1, 1, ix));
 75    	Scatter2DPtr  mult;
 76        book(mult, 1, 1, ix);
 77	for (size_t b = 0; b < temphisto.numPoints(); b++) {
 78	  const double x  = temphisto.point(b).x();
 79	  pair<double,double> ex = temphisto.point(b).xErrs();
 80	  pair<double,double> ex2 = ex;
 81	  if(ex2.first ==0.) ex2. first=0.0001;
 82	  if(ex2.second==0.) ex2.second=0.0001;
 83	  if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
 84	    mult->addPoint(x, sigma, ex, make_pair(error,error));
 85	  }
 86	  else {
 87	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
 88	  }
 89	}
 90      }
 91    }
 92
 93    //@}
 94
 95
 96    /// @name Histograms
 97    //@{
 98    CounterPtr _nMeson[6];
 99    //@}
100
101
102  };
103
104
105  // The hook for the plugin system
106  RIVET_DECLARE_PLUGIN(BESII_2008_I801210);
107
108
109}