1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/UnstableParticles.hh"
  4
  5namespace Rivet {
  6
  7
  8  /// @brief B -> Xs gamma
  9  class BELLE_2009_I825222 : public Analysis {
 10  public:
 11
 12    /// Constructor
 13    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2009_I825222);
 14
 15
 16    /// @name Analysis methods
 17    /// @{
 18
 19    /// Book histograms and initialise projections before the run
 20    void init() {
 21      // Initialise and register projections
 22      declare(UnstableParticles(Cuts::abspid==521 || Cuts::abspid==511), "UFS");
 23      // Book histograms
 24      book(_h_br, 1, 1, 1);
 25      book(_p_E,  1, 1, 2);
 26      book(_p_E2,"TMP/E2",refData<YODA::BinnedEstimate<string>>(1,1,3));
 27      book(_nBottom, "TMP/BottomCounter");
 28    }
 29
 30    void findDecayProducts(const Particle& mother,
 31                           unsigned int& nK0, unsigned int& nKp,
 32			   unsigned int& nKm) {
 33      for (const Particle & p : mother.children()) {
 34        int id = p.pid();
 35        if ( id == PID::KPLUS )      ++nKp;
 36        else if (id == PID::KMINUS ) ++nKm;
 37        else if (id == PID::K0S)     ++nK0;
 38        else if (id == PID::PI0 || id == PID::PIPLUS || id == PID::PIMINUS) {
 39	  continue;
 40        }
 41        else if ( !p.children().empty() ) {
 42          findDecayProducts(p, nK0, nKp, nKm);
 43        } 
 44      }
 45    }
 46
 47    /// Perform the per-event analysis
 48    void analyze(const Event& event) {
 49      if(_edges.empty()) {
 50        _edges = _h_br->xEdges();
 51        for(const string & en : _edges)
 52          _eCut.push_back(std::stod(en)*GeV);
 53      }
 54      // Loop over bottoms
 55      for (const Particle& bottom : apply<UnstableParticles>(event, "UFS").particles()) {
 56	// remove mixing entries etc
 57	if(bottom.children()[0].abspid()==bottom.abspid()) continue;
 58        _nBottom->fill();
 59	FourMomentum pgamma(0.,0.,0.,0.);
 60	unsigned int ngamma = 0;
 61        for (const Particle & child : bottom.children()) {
 62	  if (child.pid() == PID::PHOTON) {
 63            ngamma += 1;
 64            pgamma += child.momentum();
 65          }
 66	}
 67	if (ngamma != 1) continue;
 68        unsigned int nK0(0),nKp(0),nKm(0);
 69        FourMomentum p_tot(0,0,0,0);
 70        findDecayProducts(bottom, nK0, nKp, nKm);
 71        unsigned int nk = nKp-nKm+nK0;
 72        if (nk % 2 == 1) {
 73          const LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(bottom.momentum().betaVec());
 74          double eGamma = boost.transform(pgamma).E();
 75          for(unsigned int ix=0;ix<_eCut.size();++ix) {
 76            if(eGamma>_eCut[ix]) {
 77              _h_br->fill(_edges[ix]);
 78              _p_E ->fill(_edges[ix],eGamma);
 79              _p_E2->fill(_edges[ix],sqr(eGamma));
 80            }
 81          }
 82        }
 83      }
 84    }
 85
 86
 87    /// Normalise histograms etc., after the run
 88    void finalize() {
 89      // 1e4 for br ormalization
 90      scale(_h_br, 1e4/_nBottom->sumW());
 91      // dispersion
 92      BinnedEstimatePtr<string> dispersion;
 93      book(dispersion,1,1,3);
 94      for (auto& b : dispersion->bins()) {
 95        const auto& bE  = _p_E->bin(b.index());
 96        const auto& bE2 = _p_E2->bin(b.index());
 97        const double val = bE2.mean(2)-sqr(bE.mean(2));
 98        const double err = val*sqrt(sqr(bE2.stdErr(2)/bE2.mean(2))+4.*sqr(bE.stdErr(2)/bE.mean(2)));
 99        b.set(val,err);
100      }
101    }
102
103    /// @}
104
105
106    /// @name Histograms
107    /// @{
108    BinnedHistoPtr<string> _h_br;
109    BinnedProfilePtr<string> _p_E,_p_E2;
110    CounterPtr _nBottom;
111    vector<string> _edges;
112    vector<double> _eCut;
113    /// @}
114
115
116  };
117
118
119  RIVET_DECLARE_PLUGIN(BELLE_2009_I825222);
120
121}