1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Add a short analysis description here
 9  class BABAR_2006_I714448 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2006_I714448);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21
22      // Initialise and register projections
23      declare(UnstableParticles(),"UFS");
24      book(_h_1S, 1, 1, 1);
25      book(_h_2S, 1, 1, 2);
26    }
27
28
29    void findDecayProducts(const Particle & mother,
30			   unsigned int & nstable,
31			   Particles& pip, Particles& pim,
32			   Particles & onium) {
33      for(const Particle & p : mother.children()) {
34        int id = p.pid();
35      	if ( id == PID::PIMINUS) {
36	  pim.push_back(p);
37	  ++nstable;
38	}
39       	else if (id == PID::PIPLUS) {
40       	  pip.push_back(p);
41       	  ++nstable;
42       	}
43	else if (abs(id)%1000==553) {
44	  onium.push_back(p);
45	  ++nstable;
46	}
47	else if ( !p.children().empty() ) {
48	  findDecayProducts(p,nstable,pip,pim,onium);
49	}
50	else
51	  ++nstable;
52      }
53    }
54
55    /// Perform the per-event analysis
56    void analyze(const Event& event) {
57      // loop over unstable particles
58      for(const Particle& ups : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==300553)) {
59	unsigned int nstable(0);
60	Particles pip, pim, onium;
61	findDecayProducts(ups,nstable,pip,pim,onium);
62	// check for onium
63	if(onium.size() !=1 || nstable !=3) continue;
64	// check for pipi
65	if( ! (pip.size()==1 && pim.size() ==1) ) continue;
66	FourMomentum q = pip[0].momentum()+pim[0].momentum();
67	if(onium[0].pid()==553)
68	  _h_1S->fill(q.mass());
69	else if(onium[0].pid()==100553)
70	  _h_2S->fill(q.mass());
71      }
72    }
73
74
75    /// Normalise histograms etc., after the run
76    void finalize() {
77      normalize(_h_1S);
78      normalize(_h_2S);
79    }
80
81    /// @}
82
83
84    /// @name Histograms
85    /// @{
86    Histo1DPtr _h_1S,_h_2S;
87    /// @}
88
89
90  };
91
92
93  RIVET_DECLARE_PLUGIN(BABAR_2006_I714448);
94
95}