Rivet analyses referenceCMD3_2016_I1385598Cross section for $e^+e^-\to p\bar{p}$ between the threshold and 2 GeVExperiment: CMD3 (VEPP-2M) Inspire ID: 1385598 Status: VALIDATED Authors:
Beam energies: (0.9, 0.9); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0); (1.0, 1.0) GeV Run details:
Measurement of the cross section for $e^+e^-\to p\bar{p}$ between the threshold and 2 GeV. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples Source code: CMD3_2016_I1385598.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4
5
6namespace Rivet {
7
8
9 /// @brief e+ e- > p pbar
10 class CMD3_2016_I1385598 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(CMD3_2016_I1385598);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22
23 // Initialise and register projections
24 declare(FinalState(), "FS");
25
26 // Book histograms
27 book(_nproton, 1,1,6);
28 for (const string& en : _nproton.binning().edges<0>()) {
29 double end = en=="1900 (2012)"s ? 1.9 : std::stod(en)*MeV;
30 if(isCompatibleWithSqrtS(end)) {
31 _ecms = en;
32 break;
33 }
34 }
35 if(_ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
36 }
37
38
39 /// Perform the per-event analysis
40 void analyze(const Event& event) {
41 const FinalState& fs = apply<FinalState>(event, "FS");
42 if (fs.particles().size() != 2) vetoEvent;
43 for (const Particle& p : fs.particles()) {
44 if (p.abspid() != PID::PROTON) vetoEvent;
45 }
46 _nproton->fill(_ecms);
47 }
48
49
50 /// Normalise histograms etc., after the run
51 void finalize() {
52 scale(_nproton, crossSection()/ sumOfWeights() /nanobarn);
53 }
54
55 /// @}
56
57
58 /// @name Histograms
59 /// @{
60 BinnedHistoPtr<string> _nproton;
61 string _ecms;
62 /// @}
63
64
65 };
66
67
68 RIVET_DECLARE_PLUGIN(CMD3_2016_I1385598);
69
70
71}
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