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DM1_1979_I141565

Cross section for $e^+e^-\to p\bar{p}$ between 1.925 and 2.18 GeV
Experiment: DM1 (DCI)
Inspire ID: 141565
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B86 (1979) 395-398, 1979
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Measurement of the cross section for $e^+e^-\to p\bar{p}$ between 1.925 and 2.18 GeV.

Source code: DM1_1979_I141565.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 DM1_1979_I141565 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(DM1_1979_I141565);
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      book(_nProton,  "/TMP/nProton" );
24    }
25
26
27    /// Perform the per-event analysis
28    void analyze(const Event& event) {
29      const FinalState& fs = apply<FinalState>(event, "FS");
30      // total hadronic and muonic cross sections
31      map<long,int> nCount;
32      int ntotal(0);
33      for (const Particle& p : fs.particles()) {
34	nCount[p.pid()] += 1;
35	++ntotal;
36      }
37      if(ntotal==2 && nCount[2212]==1 && nCount[-2212]==1)
38	_nProton->fill();
39    }
40
41
42    /// Normalise histograms etc., after the run
43    void finalize() {
44      double fact = crossSection()/ sumOfWeights() /nanobarn;
45      double sigma = _nProton->val()*fact;
46      double error = _nProton->err()*fact;
47      Scatter2D temphisto(refData(1, 1, 1));
48      Scatter2DPtr mult;
49      book(mult, 1, 1, 1);
50      for (size_t b = 0; b < temphisto.numPoints(); b++) {
51	const double x  = temphisto.point(b).x();
52	pair<double,double> ex = temphisto.point(b).xErrs();
53	pair<double,double> ex2 = ex;
54	if(ex2.first ==0.) ex2. first=0.0001;
55	if(ex2.second==0.) ex2.second=0.0001;
56	if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
57	  mult->addPoint(x, sigma, ex, make_pair(error,error));
58	}
59	else {
60	  mult->addPoint(x, 0., ex, make_pair(0.,.0));
61	}
62      }
63    }
64
65    //@}
66
67
68    /// @name Histograms
69    //@{
70    CounterPtr _nProton;
71    //@}
72
73
74  };
75
76
77  // The hook for the plugin system
78  RIVET_DECLARE_PLUGIN(DM1_1979_I141565);
79
80
81}