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 Bbar0 -> Lambda_c+ Lambdabar_c- Kbar0
10  class BELLE_2018_I1679584 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2018_I1679584);
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( 4122);
26      B0.addStable(-4122);
27      B0.addStable( 310);
28      declare(B0, "B0");
29      // histos
30      for(unsigned int ix=0;ix<2;++ix)
31	book(_h[ix],1+ix,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   = { { 4122,1},{-4122,1}, { 310,1}};
38      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
39      // loop over particles
40      for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
41      	if(!B0.modeMatches(ix,3,mode))
42      	  continue;
43	const Particle & LamC    = B0.decayProducts()[ix].at( 4122)[0];
44	const Particle & LamCBar = B0.decayProducts()[ix].at(-4122)[0];
45	const Particle & K0      = B0.decayProducts()[ix].at(  310)[0];
46	if(B0.decaying()[ix].pid()<0)
47	  _h[0]->fill((LamC   .momentum()+K0.momentum()).mass());
48	else
49	  _h[0]->fill((LamCBar.momentum()+K0.momentum()).mass());
50	_h[1]->fill((LamC.momentum()+LamCBar.momentum()).mass());
51      }
52    }
53
54
55    /// Normalise histograms etc., after the run
56    void finalize() {
57      for(unsigned int ix=0;ix<2;++ix)
58	normalize(_h[ix],1.,false);
59    }
60
61    /// @}
62
63
64    /// @name Histograms
65    /// @{
66    Histo1DPtr _h[2];
67    /// @}
68
69
70  };
71
72
73  RIVET_DECLARE_PLUGIN(BELLE_2018_I1679584);
74
75}