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## Rivet analyses reference

### CELLO_1981_I166365

Measurement of $R$ for energies between 33 and 36.7 GeV
Experiment: CELLO (PETRA)
Inspire ID: 166365
Status: VALIDATED
Authors:
• Peter Richardson
No references listed
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 14 and 46.6 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: CELLO_1981_I166365.cc
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/FinalState.hh" namespace Rivet { /// @brief Add a short analysis description here class CELLO_1981_I166365 : public Analysis { public: /// Constructor DEFAULT_RIVET_ANALYSIS_CTOR(CELLO_1981_I166365); /// @name Analysis methods //@{ /// Book histograms and initialise projections before the run void init() { // Initialise and register projections declare(FinalState(), "FS"); // counters for R 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(event, "FS"); map nCount; int ntotal(0); unsigned int nCharged(0); for (const Particle& p : fs.particles()) { nCount[p.pid()] += 1; ++ntotal; if(PID::isCharged(p.pid())) ++nCharged; } // 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() { Scatter1D R = *_c_hadrons/ *_c_muons; double rval = R.point(0).x(); pair rerr = R.point(0).xErrs(); double fact = crossSection()/ sumOfWeights() /picobarn; double sig_h = _c_hadrons->val()*fact; double err_h = _c_hadrons->err()*fact; double sig_m = _c_muons ->val()*fact; double err_m = _c_muons ->err()*fact; Scatter2D temphisto(refData(1, 1, 1)); Scatter2DPtr hadrons; book(hadrons, "sigma_hadrons"); Scatter2DPtr muons; book(muons, "sigma_muons" ); Scatter2DPtr mult; book(mult, 1, 1, 1); for (size_t b = 0; b < temphisto.numPoints(); b++) { const double x = temphisto.point(b).x(); pair ex = temphisto.point(b).xErrs(); pair 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, rval, ex, rerr); hadrons->addPoint(x, sig_h, ex, make_pair(err_h,err_h)); muons ->addPoint(x, sig_m, ex, make_pair(err_m,err_m)); } else { mult ->addPoint(x, 0., ex, make_pair(0.,.0)); hadrons->addPoint(x, 0., ex, make_pair(0.,.0)); muons ->addPoint(x, 0., ex, make_pair(0.,.0)); } } } //@} /// @name Histograms //@{ CounterPtr _c_hadrons, _c_muons; //@} }; // The hook for the plugin system DECLARE_RIVET_PLUGIN(CELLO_1981_I166365); }