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TOPAZ_1993_I353845

Cross section in $e^+e^-\to$hadrons for energies between 57.37 and 59.84 GeV
Experiment: TOPAZ (Tristan)
Inspire ID: 353845
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B304 (1993) 373-380, 1993
Beams: e- e+
Beam energies: ANY
Run details:
  • e+ e- to hadrons and e+ e- to mu+ mu-

Measurement of the hadronic cross section in $e^+e^-$ collisions by TOPAZ for energies between 57.37 and 59.84 GeV. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio $R$ can be recalcuated if runs are combined.

Source code: TOPAZ_1993_I353845.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 TOPAZ_1993_I353845 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(TOPAZ_1993_I353845);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");

      // Book histograms
      book(_c_hadrons, "/TMP/sigma_hadrons");
      book(_c_muons, "/TMP/sigma_muons");
    }


    /// 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;
      }
      // mu+mu- + photons
      if(nCount[-13]==1 and nCount[13]==1 &&
	 ntotal==2+nCount[22])
	_c_muons->fill();
      // everything else
      else
	_c_hadrons->fill();
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      double fact = crossSection()/ sumOfWeights() /picobarn;
      for(unsigned int ix=2;ix<5;ix+=2) {
	double sigma,error;
	if(ix==2) {
	  sigma = _c_hadrons->val()*fact;
	  error = _c_hadrons->err()*fact;
	}
	else {
	  sigma = _c_muons  ->val()*fact;
	  error = _c_muons  ->err()*fact;
	}
	Scatter2D temphisto(refData(ix, 1, 1));
	Scatter2DPtr mult;
	book(mult, ix, 1, 1);
	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 _c_hadrons, _c_muons;
    //@}


  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(TOPAZ_1993_I353845);


}