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 D_s+ -> pi+pi+pi-
10  class BABAR_2008_I792597 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2008_I792597);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      // Initialise and register projections
23      UnstableParticles ufs = UnstableParticles(Cuts::abspid==431);
24      declare(ufs, "UFS");
25      DecayedParticles DS(ufs);
26      DS.addStable(PID::PI0);
27      DS.addStable(PID::K0S);
28      declare(DS,"DS");
29      // histos
30      book(_h_pippim[0],1,1,3);
31      book(_h_pippip   ,1,1,4);
32      book(_h_pippim[1],1,1,1);
33      book(_h_pippim[2],1,1,2);
34      book(_dalitz, "dalitz",50,0.,3.5,50,0.0,3.5);
35    }
36
37    /// Perform the per-event analysis
38    void analyze(const Event& event) {
39      static const map<PdgId,unsigned int> & mode   = { { 211,2}, {-211,1}};
40      static const map<PdgId,unsigned int> & modeCC = { {-211,2}, { 211,1}};
41      DecayedParticles DS = apply<DecayedParticles>(event, "DS");
42      // loop over particles
43      for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
44	int sign = 1;
45	if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,3,mode)) {
46	  sign=1;
47	}
48	else if  (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,3,modeCC)) {
49	  sign=-1;
50	}
51	else
52	  continue;
53	const Particles & pip = DS.decayProducts()[ix].at( sign*211);
54	const Particle  & pim = DS.decayProducts()[ix].at(-sign*211)[0];
55	// kinematic variables
56	double x[3] = {(pim.momentum()+pip[0].momentum()).mass2(),
57		       (pim.momentum()+pip[1].momentum()).mass2(),
58		       (pip[0].momentum()+pip[1].momentum()).mass2()};
59	if(x[0]>x[1]) swap(x[0],x[1]);
60	_dalitz->fill(x[0],x[1]);
61	_dalitz->fill(x[1],x[0]);
62	// fill plots
63	_h_pippim[0]->fill(x[0]);
64	_h_pippim[0]->fill(x[1]);
65	_h_pippim[1]->fill(x[0]);
66	_h_pippim[2]->fill(x[1]);
67	_h_pippip   ->fill(x[2]);
68      }
69    }
70
71
72    /// Normalise histograms etc., after the run
73    void finalize() {
74      for(unsigned int ix=0;ix<3;++ix)
75	normalize(_h_pippim[ix]);
76      normalize(_h_pippip);
77      normalize(_dalitz);
78    }
79
80    /// @}
81
82
83    /// @name Histograms
84    /// @{
85    Histo1DPtr _h_pippim[3],_h_pippip;
86    Histo2DPtr _dalitz;
87    /// @}
88
89
90  };
91
92
93  RIVET_DECLARE_PLUGIN(BABAR_2008_I792597);
94
95}