Rivet analyses referenceKLOE_2013_I1186739$\eta\to\pi^+\pi^-\gamma$ decaysExperiment: KLOE (DAPHNE) Inspire ID: 1186739 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Differential decay rates for $\eta\to \pi^+\pi^-\gamma$ decays. Data read from plots and error bars are the size of the point. The data is corrected and background subtracted. Source code: KLOE_2013_I1186739.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4#include "Rivet/Projections/DecayedParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief eta -> pi+pi- gamma decay
10 class KLOE_2013_I1186739 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(KLOE_2013_I1186739);
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 UnstableParticles ufs = UnstableParticles(Cuts::abspid==221);
25 declare(ufs, "UFS");
26 DecayedParticles ETA(ufs);
27 ETA.addStable(PID::PI0);
28 declare(ETA, "ETA");
29
30 // Book histograms
31 book(_h_m, 1, 1, 1);
32 }
33
34
35 /// Perform the per-event analysis
36 void analyze(const Event& event) {
37 static const map<PdgId,unsigned int> & mode = { { PID::PIPLUS,1}, { PID::PIMINUS ,1}, { PID::GAMMA,1}};
38 DecayedParticles ETA = apply<DecayedParticles>(event, "ETA");
39 // loop over particles
40 for(unsigned int ix=0;ix<ETA.decaying().size();++ix) {
41 if (!ETA.modeMatches(ix,3,mode)) continue;
42 const Particle & pip = ETA.decayProducts()[ix].at( PID::PIPLUS )[0];
43 const Particle & pim = ETA.decayProducts()[ix].at( PID::PIMINUS)[0];
44 _h_m->fill((pip.momentum()+pim.momentum()).mass()/MeV);
45 }
46 }
47
48
49 /// Normalise histograms etc., after the run
50 void finalize() {
51 normalize(_h_m);
52 }
53
54 /// @}
55
56
57 /// @name Histograms
58 /// @{
59 Histo1DPtr _h_m;
60 /// @}
61
62
63 };
64
65
66 RIVET_DECLARE_PLUGIN(KLOE_2013_I1186739);
67
68}
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