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 Xi_c+ spectrum
 10  class ARGUS_1990_I296522 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1990_I296522);
 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_obs1,1,1,1);
 27      book(_h_obs2,1,1,2);
 28      book(_h_obs3,1,1,3);
 29      book(_h_all1,2,1,1);
 30      book(_h_all2,2,1,2);
 31      book(_h_all3,2,1,3);
 32      book(_h_x,3,1,1);
 33    }
 34
 35    void findDecayProducts(Particle parent, Particles & Xi, Particles & pions,unsigned int & nstable) {
 36      for(const Particle & p : parent.children()) {
 37	if(p.abspid()==PID::XIMINUS) {
 38	  Xi.push_back(p);
 39	  ++nstable;
 40	}
 41	else if(p.abspid()==PID::PIPLUS) {
 42	  pions.push_back(p);
 43	  ++nstable;
 44	}
 45	else if(!p.children().empty())
 46	  findDecayProducts(p,Xi,pions,nstable);
 47	else
 48	  ++nstable;
 49      }
 50    }
 51
 52    /// Perform the per-event analysis
 53    void analyze(const Event& event) {
 54      static const int idXip = 4232,idXi0 = 4132;
 55      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
 56      const double Emax = ( beams.first.p3().mod() + beams.second.p3().mod() ) / 2.0;
 57      const double Pmax = sqrt(sqr(Emax)-sqr(2.468));
 58      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
 59      for (const Particle& p : ufs.particles(Cuts::abspid==idXip or Cuts::abspid==idXi0)) {
 60	double xp = p.momentum().p3().mod()/Pmax;
 61	_h_x->fill(xp);
 62	Particles Xi,pions;
 63	unsigned int nstable(0);
 64	findDecayProducts(p,Xi,pions,nstable);
 65	if(nstable==2&&Xi.size()==1&&pions.size()==1) {
 66	  _h_obs1->fill(xp);
 67	  _h_all1->fill(xp);
 68	}
 69	else if(nstable==3&&Xi.size()==1&&pions.size()==2) {
 70	  _h_obs3->fill(xp);
 71	  _h_all3->fill(xp);
 72	}
 73	else if(nstable==4&&Xi.size()==1&&pions.size()==3) {
 74	  _h_obs2->fill(xp);
 75	  _h_all2->fill(xp);
 76	}
 77      }
 78    }
 79
 80
 81    /// Normalise histograms etc., after the run
 82    void finalize() {
 83      normalize(_h_x);
 84      scale(_h_obs1,0.5*crossSection()/picobarn/sumOfWeights());
 85      scale(_h_obs2,0.5*crossSection()/picobarn/sumOfWeights());
 86      scale(_h_obs3,0.5*crossSection()/picobarn/sumOfWeights());
 87      scale(_h_all1,    crossSection()/picobarn/sumOfWeights());
 88      scale(_h_all2,    crossSection()/picobarn/sumOfWeights());
 89      scale(_h_all3,    crossSection()/picobarn/sumOfWeights());
 90    }
 91
 92    /// @}
 93
 94
 95    /// @name Histograms
 96    /// @{
 97    Histo1DPtr _h_obs1,_h_obs2,_h_obs3,_h_all1,_h_all2,_h_all3;
 98    Histo1DPtr _h_x;
 99    /// @}
100
101
102  };
103
104
105  RIVET_DECLARE_PLUGIN(ARGUS_1990_I296522);
106
107}