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TASSO_1980_I143690

Measurement of $R$ for energies between 12 and 39 GeV
Experiment: TASSO (PETRA)
Inspire ID: 143690
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C4 (1980) 87, 1980
Beams: e- e+
Beam energies: ANY
Run details:
  • e+ e- to hadrons and e+ e- to mu+ mu- (for normalization)

Measurement of $R$ in $e^+e^-$ collisions for energies between 12 and 39 GeV. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio $R$ can be recalculated if runs are combined.

Source code: TASSO_1980_I143690.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 TASSO_1980_I143690 : public Analysis {
 10  public:
 11
 12    /// Constructor
 13    RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1980_I143690);
 14
 15
 16    /// @name Analysis methods
 17    //@{
 18
 19    /// Book histograms and initialise projections before the run
 20    void init() {
 21      // Initialise and register projections
 22      declare(FinalState(), "FS");
 23      // counters for R
 24      book(_c_hadrons, "/TMP/sigma_hadrons");
 25      book(_c_muons, "/TMP/sigma_muons");
 26    }
 27
 28
 29    /// Perform the per-event analysis
 30    void analyze(const Event& event) {
 31      const FinalState& fs = apply<FinalState>(event, "FS");
 32
 33      map<long,int> nCount;
 34      int ntotal(0);
 35      unsigned int nCharged(0);
 36      for (const Particle& p : fs.particles()) {
 37	nCount[p.pid()] += 1;
 38	++ntotal;
 39	if(PID::isCharged(p.pid())) ++nCharged;
 40      }
 41      // mu+mu- + photons
 42      if(nCount[-13]==1 and nCount[13]==1 &&
 43	 ntotal==2+nCount[22])
 44	_c_muons->fill();
 45      // everything else
 46      else {
 47	_c_hadrons->fill();
 48      }
 49    }
 50
 51
 52    /// Normalise histograms etc., after the run
 53    void finalize() {
 54      Scatter1D R = *_c_hadrons/ *_c_muons;
 55      double              rval = R.point(0).x();
 56      pair<double,double> rerr = R.point(0).xErrs();
 57      double fact = crossSection()/ sumOfWeights() /picobarn;
 58      double sig_h = _c_hadrons->val()*fact;
 59      double err_h = _c_hadrons->err()*fact;
 60      double sig_m = _c_muons  ->val()*fact;
 61      double err_m = _c_muons  ->err()*fact;
 62      Scatter2D temphisto(refData(1, 1, 1));
 63      Scatter2DPtr hadrons;
 64      book(hadrons, "sigma_hadrons");
 65      Scatter2DPtr muons;
 66      book(muons, "sigma_muons"  );
 67      Scatter2DPtr mult;
 68      book(mult, 1, 1, 1);
 69      for (size_t b = 0; b < temphisto.numPoints(); b++) {
 70	const double x  = temphisto.point(b).x();
 71	pair<double,double> ex = temphisto.point(b).xErrs();
 72	pair<double,double> ex2 = ex;
 73	if(ex2.first ==0.) ex2. first=0.0001;
 74	if(ex2.second==0.) ex2.second=0.0001;
 75	if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
 76	  mult   ->addPoint(x, rval, ex, rerr);
 77	  hadrons->addPoint(x, sig_h, ex, make_pair(err_h,err_h));
 78	  muons  ->addPoint(x, sig_m, ex, make_pair(err_m,err_m));
 79	}
 80	else {
 81	  mult   ->addPoint(x, 0., ex, make_pair(0.,.0));
 82	  hadrons->addPoint(x, 0., ex, make_pair(0.,.0));
 83	  muons  ->addPoint(x, 0., ex, make_pair(0.,.0));
 84	}
 85      }
 86    }
 87
 88    //@}
 89
 90
 91    /// @name Histograms
 92    //@{
 93    CounterPtr _c_hadrons, _c_muons;
 94    //@}
 95
 96
 97  };
 98
 99
100  // The hook for the plugin system
101  RIVET_DECLARE_PLUGIN(TASSO_1980_I143690);
102
103
104}