rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

BES_1995_I39870

Measurement of the hadronic cross section for energies between 3.08 and 3.116 GeV
Experiment: BES (BEPC)
Inspire ID: 39870
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B355 (1995) 374-380, 1995
Beams: e- e+
Beam energies: ANY
Run details:
  • e+ e- to hadrons and e+ e- to mu+ mu- (for normalization)

Measurement of the hadronic cross section in $e^+e^-$ collisions by BES for energies between 3.08 and 3.116 GeV.

Source code: BES_1995_I39870.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
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"

namespace Rivet {


  /// @brief Add a short analysis description here
  class BES_1995_I39870 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(BES_1995_I39870);


    /// @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");
    }


    /// 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])
	vetoEvent;
      // everything else
      else
	_c_hadrons->fill();
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      double fact = crossSection()/ sumOfWeights() /nanobarn;
      double sig_h = _c_hadrons->val()*fact;
      double err_h = _c_hadrons->err()*fact;
      Scatter2D temphisto(refData(1, 1, 1));
      Scatter2DPtr hadrons;
      book(hadrons, 1, 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)) {
	  hadrons->addPoint(x, sig_h, ex, make_pair(err_h,err_h));
	}
	else {
	  hadrons->addPoint(x, 0., ex, make_pair(0.,.0));
	}
      }

    }

    //@}


    /// @name Histograms
    //@{
    CounterPtr _c_hadrons;
    //@}


  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(BES_1995_I39870);


}