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 D_1+ and D_2 spectra
 10  class CLEOII_1994_I378319 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1994_I378319);
 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_D2_cTheta,2,1,1);
 27      book(_h_D2_x     ,4,1,1);
 28      book(_h_D1_cTheta,3,1,1);
 29      book(_h_D1_x     ,4,1,2);
 30      for(unsigned int ix=0;ix<3;++ix)
 31	book(_r[ix],5,1,ix+1);
 32    }
 33
 34
 35    /// Perform the per-event analysis
 36    void analyze(const Event& event) {
 37      static const int idD1 = 10413;
 38      static const int idD2 = 415;
 39      // Get beams and average beam momentum
 40      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
 41      const double Emax = ( beams.first.p3().mod() + beams.second.p3().mod() ) / 2.0;
 42      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
 43      for (const Particle& p : ufs.particles(Cuts::abspid==idD1 or Cuts::abspid==idD2)) {
 44	if(p.abspid()==idD1) {
 45	  // spectrum
 46	  double Pmax = sqrt(sqr(Emax)-sqr(2.421));
 47	  double xp = p.momentum().p3().mod()/Pmax;
 48	  _h_D1_x->fill(xp);
 49	}
 50	else {
 51	  double Pmax = sqrt(sqr(Emax)-sqr(2.461));
 52	  double xp = p.momentum().p3().mod()/Pmax;
 53	  _h_D2_x->fill(xp);
 54	}
 55	int sign = p.pid()/p.abspid();
 56	Particle Dstar;
 57	if(p.children().size()!=2) continue;
 58	if(p.children()[0].pid()==sign*423 &&
 59	   p.children()[1].pid()==sign*211) {
 60	  Dstar = p.children()[0];
 61	}
 62	else if(p.children()[1].pid()==sign*423 &&
 63		p.children()[0].pid()==sign*211) {
 64	  Dstar = p.children()[1];
 65	}
 66	else if(p.children()[0].pid()==sign*421 &&
 67	   p.children()[1].pid()==sign*211) {
 68	  if(p.abspid()!=idD1) _r[0]->fill(0.5);
 69	  continue;
 70	}
 71	else if(p.children()[1].pid()==sign*421 &&
 72		p.children()[0].pid()==sign*211) {
 73	  if(p.abspid()!=idD1) _r[0]->fill(0.5);
 74	  continue;
 75	}
 76	else {
 77	  continue;
 78	}
 79	if(p.abspid()==idD1)
 80	  _r[2]->fill(0.5);
 81	else
 82	  _r[1]->fill(0.5);
 83	if(Dstar.children().size()!=2) continue;
 84	Particle pion;
 85	if(Dstar.children()[0].pid()== 111 &&
 86	   Dstar.children()[1].pid()== sign*421) {
 87	  pion = Dstar.children()[0];
 88	}
 89	else if(Dstar.children()[1].pid()== 111 &&
 90		Dstar.children()[0].pid()== sign*421) {
 91	  pion = Dstar.children()[1];
 92	}
 93	else
 94	  continue;
 95	// first boost to the D_1,2 rest frame
 96	LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
 97	FourMomentum pDstar = boost1.transform(Dstar.momentum());
 98	FourMomentum pPion  = boost1.transform(pion .momentum());
 99	// to D* rest frame
100	LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pDstar.betaVec());
101	Vector3 axis = pDstar.p3().unit();
102	FourMomentum pp = boost2.transform(pPion);
103	// calculate angle
104	double cTheta = pp.p3().unit().dot(axis);
105	if(p.abspid()==idD1)
106	  _h_D1_cTheta->fill(cTheta);
107	else
108	  _h_D2_cTheta->fill(cTheta);
109      }
110    }
111
112    /// Normalise histograms etc., after the run
113    void finalize() {
114      normalize(_h_D2_cTheta);
115      normalize(_h_D2_x     );
116      normalize(_h_D1_cTheta);
117      normalize(_h_D1_x     );
118      for(unsigned int ix=0;ix<3;++ix)
119	scale(_r[ix],crossSection()/sumOfWeights()/picobarn);
120    }
121
122    /// @}
123
124
125    /// @name Histograms
126    /// @{
127    Histo1DPtr _h_D2_cTheta,_h_D2_x,_h_D1_cTheta,_h_D1_x;
128    Histo1DPtr _r[3];
129    /// @}
130
131
132  };
133
134
135  RIVET_DECLARE_PLUGIN(CLEOII_1994_I378319);
136
137}