Rivet analyses referenceBESII_2002_I552757Measurement of $R$ for energies between 2.2 and 4.8 GeVExperiment: BESII (BEPC) Inspire ID: 552757 Status: VALIDATED Authors:
Beam energies: ANY Run details:
Measurement of $R$ in $e^+e^-$ collisions by BESII for energies between 2.2 and 4.8 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: BESII_2002_I552757.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4
5namespace Rivet {
6
7
8 /// @brief Measurement of R for energies between 2.2 and 4.8 GeV
9 class BESII_2002_I552757 : public Analysis {
10 public:
11
12 /// Constructor
13 RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2002_I552757);
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
24 // Book histograms
25 book(_c_hadrons, "/TMP/sigma_hadrons");
26 book(_c_muons, "/TMP/sigma_muons");
27 }
28
29
30 /// Perform the per-event analysis
31 void analyze(const Event& event) {
32 const FinalState& fs = apply<FinalState>(event, "FS");
33
34 map<long,int> nCount;
35 int ntotal(0);
36 for (const Particle& p : fs.particles()) {
37 nCount[p.pid()] += 1;
38 ++ntotal;
39 }
40 // mu+mu- + photons
41 if (nCount[-13]==1 && nCount[13]==1 && ntotal==2+nCount[22])
42 _c_muons->fill();
43 // everything else
44 else
45 _c_hadrons->fill();
46 }
47
48
49 /// Normalise histograms etc., after the run
50 void finalize() {
51 Estimate0D R = *_c_hadrons / *_c_muons;
52 double fact = crossSection()/ sumOfWeights() /nanobarn;
53 double sig_h = _c_hadrons->val()*fact;
54 double err_h = _c_hadrons->err()*fact;
55 double sig_m = _c_muons ->val()*fact;
56 double err_m = _c_muons ->err()*fact;
57 Estimate1DPtr hadrons, muons, mult;
58 book(hadrons, "sigma_hadrons");
59 book(muons, "sigma_muons" );
60 book(mult, 1, 1, 1);
61 for (auto& b : mult->bins()) {
62 if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
63 b.set(R.val(), R.errPos());
64 hadrons->bin(b.index()).set(sig_h, err_h);
65 muons ->bin(b.index()).set(sig_m, err_m);
66 }
67 }
68 }
69
70 /// @}
71
72
73 /// @name Histograms
74 /// @{
75 CounterPtr _c_hadrons, _c_muons;
76 /// @}
77
78
79 };
80
81
82 RIVET_DECLARE_PLUGIN(BESII_2002_I552757);
83
84}
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