1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/Beam.hh"
 4#include "Rivet/Projections/UnstableParticles.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief Sigma*_c spectra
10  class CLEOII_1997_I424575 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1997_I424575);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      // projections
23      declare(Beam(), "Beams");
24      declare(UnstableParticles(), "UFS");
25      // book histos
26      book(_h_cTheta,2,1,1);
27      book(_h_x     ,3,1,1);
28    }
29
30
31    /// Perform the per-event analysis
32    void analyze(const Event& event) {
33      // Get beams and average beam momentum
34      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
35      const double Emax = ( beams.first.p3().mod() + beams.second.p3().mod() ) / 2.0;
36      const double Pmax = sqrt(sqr(Emax)-sqr(2.518));
37      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
38      for (const Particle& p : ufs.particles(Cuts::abspid==4114 or Cuts::abspid==4224)) {
39	// momentum fraction
40	double xp = p.momentum().p3().mod()/Pmax;
41        _h_x->fill(xp);
42	if(p.children().size()!=2) continue;
43	// decay angle
44	Particle pi;
45	int sign = p.pid()/p.abspid();
46	if(p.abspid()==4224) {
47	  if(p.children()[0].pid() == sign*4122 &&
48	     p.children()[1].pid() == sign*211 ) {
49	    pi=p.children()[1];
50	  }
51	  else if(p.children()[1].pid() == sign*4122 &&
52		  p.children()[0].pid() == sign*211 ) {
53	    pi=p.children()[0];
54	  }
55	  else
56	    continue;
57	}
58	else {
59	  if(p.children()[0].pid() == sign*4122 &&
60	     p.children()[1].pid() == -sign*211 ) {
61	    pi=p.children()[1];
62	  }
63	  else if(p.children()[1].pid() == sign*4122 &&
64		  p.children()[0].pid() == -sign*211 ) {
65	    pi=p.children()[0];
66	  }
67	  else
68	    continue;
69	}
70	LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
71	Vector3 axis = boost.transform(pi.momentum()).p3().unit();
72	double cosL  = axis.dot(p.momentum().p3().unit());
73	_h_cTheta->fill(cosL);
74      }
75    }
76
77
78    /// Normalise histograms etc., after the run
79    void finalize() {
80      normalize(_h_x     ,1.,false);
81      normalize(_h_cTheta,1.,false);
82    }
83
84    /// @}
85
86
87    /// @name Histograms
88    /// @{
89    Histo1DPtr _h_x,_h_cTheta;
90    /// @}
91
92
93  };
94
95
96  RIVET_DECLARE_PLUGIN(CLEOII_1997_I424575);
97
98}