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BELLE_2019_I1729311

$B^0\to p \bar{p}\pi^0$
Experiment: BELLE (KEKB)
Inspire ID: 1729311
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 99 (2019) 9, 091104
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing B0 originally e+e- at Upsilon(4S)

Measurement of the mass distributions in the decay $B^0\to p \bar{p}\pi^0$. 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}