Rivet analyses referenceBELLE_2019_I1729311B0→pˉpπ0Experiment: BELLE (KEKB) Inspire ID: 1729311 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay B0→pˉpπ0. The data were read from the plots in the paper, but is corrected for detector efficiency. Source code: BELLE_2019_I1729311.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 B0 -> p pbar pi0
10 class BELLE_2019_I1729311 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2019_I1729311);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 UnstableParticles ufs = UnstableParticles(Cuts::abspid==511);
23 declare(ufs, "UFS");
24 DecayedParticles B0(ufs);
25 B0.addStable(PID::PI0);
26 B0.addStable(PID::K0S);
27 B0.addStable(PID::ETA);
28 B0.addStable(PID::ETAPRIME);
29 declare(B0, "B0");
30 book(_h[0],1,1,1);
31 for(unsigned int ix=0;ix<2;++ix)
32 book(_h[ix+1],2,1,1+ix);
33 book(_dalitz, "dalitz",50,1.,20.,50,1.,20.);
34 }
35
36
37 /// Perform the per-event analysis
38 void analyze(const Event& event) {
39 static const map<PdgId,unsigned int> & mode = { { 2212,1}, {-2212,1}, { 111,1} };
40 DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
41 // loop over particles
42 for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
43 if(!B0.modeMatches(ix,3,mode)) continue;
44 int sign = B0.decaying()[ix].pid()/511;
45 const Particle & pi0 = B0.decayProducts()[ix].at( 111)[0];
46 const Particle & pp = B0.decayProducts()[ix].at( sign*2212)[0];
47 const Particle & pbar = B0.decayProducts()[ix].at(-sign*2212)[0];
48 double mminus = (pbar.momentum()+pi0.momentum()).mass2();
49 double mplus = (pp .momentum()+pi0.momentum()).mass2();
50 _h[0]->fill((pp.momentum()+pbar.momentum()).mass());
51 _h[1]->fill(sqrt(mplus ));
52 _h[2]->fill(sqrt(mminus));
53 _dalitz->fill(mplus,mminus);
54 }
55 }
56
57
58 /// Normalise histograms etc., after the run
59 void finalize() {
60 normalize(_dalitz);
61 for(unsigned int ix=0;ix<3;++ix)
62 normalize(_h[ix]);
63 }
64
65 /// @}
66
67
68 /// @name Histograms
69 /// @{
70 Histo1DPtr _h[3];
71 Histo2DPtr _dalitz;
72 /// @}
73
74
75 };
76
77
78 RIVET_DECLARE_PLUGIN(BELLE_2019_I1729311);
79
80}
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