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 -> pi+ pi- K*0
10  class BABAR_2012_I1081760 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2012_I1081760);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      // projections
23      UnstableParticles ufs = UnstableParticles(Cuts::abspid==511);
24      declare(ufs, "UFS");
25      DecayedParticles B0(ufs);
26      B0.addStable( 313);
27      B0.addStable(-313);
28      declare(B0, "B0");
29      // histogram
30      book(_h,1,1,1);
31    }
32
33
34    /// Perform the per-event analysis
35    void analyze(const Event& event) {
36      static const map<PdgId,unsigned int> & mode   = { { 211,1}, {-211,1}, { 313,1}};
37      static const map<PdgId,unsigned int> & modeCC = { { 211,1}, {-211,1}, {-313,1}};
38      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
39      for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
40      	int sign = 1;
41      	if (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode))        sign= 1;
42      	else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,modeCC)) sign=-1;
43	else continue;
44	const Particle & pip = B0.decayProducts()[ix].at( sign*211)[0];
45	const Particle & pim = B0.decayProducts()[ix].at(-sign*211)[0];
46	_h->fill((pip.momentum()+pim.momentum()).mass());
47      }
48    }
49
50
51    /// Normalise histograms etc., after the run
52    void finalize() {
53      normalize(_h,1.,false);
54    }
55
56    /// @}
57
58
59    /// @name Histograms
60    /// @{
61    Histo1DPtr _h;
62    /// @}
63
64
65  };
66
67
68  RIVET_DECLARE_PLUGIN(BABAR_2012_I1081760);
69
70}