Rivet analyses referenceBESIII_2017_I1509241Cross section for $e^+e^-\to p \bar{p} \pi^0$ at energies between 4.008 and 4.600 GeVExperiment: BESIII (BEPC) Inspire ID: 1509241 Status: VALIDATED Authors:
Beam energies: (2.0, 2.0); (2.0, 2.0); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.3, 2.3) GeV Run details:
Cross section for $e^+e^-\to p \bar{p} \pi^0$ at energies between 4.008 and 4.600 GeV measured by the BESIII collaboration. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples. Source code: BESIII_2017_I1509241.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4
5namespace Rivet {
6
7
8 /// @brief Cross section for $e^+e^-\to p \bar{p} \pi^0$ at energies between 4.008 and 4.600 GeV
9 class BESIII_2017_I1509241 : public Analysis {
10 public:
11
12 /// Constructor
13 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2017_I1509241);
14
15
16 /// @name Analysis methods
17 /// @{
18
19 /// Book histograms and initialise projections before the run
20 void init() {
21
22 // Initialise and register projections
23 declare(FinalState(), "FS");
24
25 // Book histograms
26 book(_nproton, 1, 1, 1);
27
28 for (const string& en : _nproton.binning().edges<0>()) {
29 const double end = std::stod(en)*GeV;
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
40 /// Perform the per-event analysis
41 void analyze(const Event& event) {
42 const FinalState& fs = apply<FinalState>(event, "FS");
43 if (fs.particles().size()!=3) vetoEvent;
44 for (const Particle& p : fs.particles()) {
45 if (abs(p.pid())!=PID::PROTON && p.pid()!=PID::PI0) vetoEvent;
46 }
47 _nproton->fill(_ecms);
48 }
49
50
51 /// Normalise histograms etc., after the run
52 void finalize() {
53 scale(_nproton, crossSection()/ sumOfWeights() /picobarn);
54 }
55
56 /// @}
57
58
59 /// @name Histograms
60 /// @{
61 BinnedHistoPtr<string> _nproton;
62 string _ecms;
63 /// @}
64
65
66 };
67
68
69 RIVET_DECLARE_PLUGIN(BESIII_2017_I1509241);
70
71}
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