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Rivet analyses reference

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
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"

namespace Rivet {


  /// @brief Add a short analysis description here
  class BESII_2008_I801210 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(BESII_2008_I801210);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(FinalState(), "FS");

      // Book histograms
      for(unsigned int ix=1;ix<6;++ix) {
	stringstream ss;
	ss << "TMP/n" << ix;
	book(_nMeson[ix], ss.str());
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");

      map<long,int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
	nCount[p.pid()] += 1;
	++ntotal;
      }
      if(nCount[111]!=2) vetoEvent;

      if(ntotal==4) {
	if(nCount[211]==1 && nCount[-211]==1)
	  _nMeson[1]->fill();
	else if(nCount[321]==1 && nCount[-321]==1)
	  _nMeson[2]->fill();
      }
      else if(ntotal==6) {
	if(nCount[211]==2 && nCount[-211]==2)
	  _nMeson[3]->fill();
	else if(nCount[321]==1 && nCount[-321]==1 &&
		nCount[211]==1 && nCount[-211]==1)
	  _nMeson[4]->fill();
      }
      else if(ntotal==8) {
	if(nCount[211]==3 && nCount[-211]==3)
	  _nMeson[5]->fill();
      }
      
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=1;ix<6;++ix) {
	double sigma = _nMeson[ix]->val();
	double error = _nMeson[ix]->err();
    	sigma *= crossSection()/ sumOfWeights() /picobarn;
    	error *= crossSection()/ sumOfWeights() /picobarn; 
	Scatter2D temphisto(refData(1, 1, ix));
    	Scatter2DPtr  mult;
        book(mult, 1, 1, ix);
	for (size_t b = 0; b < temphisto.numPoints(); b++) {
	  const double x  = temphisto.point(b).x();
	  pair<double,double> ex = temphisto.point(b).xErrs();
	  pair<double,double> ex2 = ex;
	  if(ex2.first ==0.) ex2. first=0.0001;
	  if(ex2.second==0.) ex2.second=0.0001;
	  if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
	    mult->addPoint(x, sigma, ex, make_pair(error,error));
	  }
	  else {
	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
	  }
	}
      }
    }

    //@}


    /// @name Histograms
    //@{
    CounterPtr _nMeson[6];
    //@}


  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(BESII_2008_I801210);


}