Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief e+ e- > pi+ pi- pi0 chi_b
  class BELLE_2014_I1309588 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2014_I1309588);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");
      for (unsigned int ix=0; ix<3; ++ix) {
        for (unsigned int iy=0;iy<2;++iy) {
          book(_h[ix][iy],1+ix,1,1+iy);
        }
      }
    }

    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
      for (const Particle &child : p.children()) {
        if (child.children().empty()) {
          --nRes[child.pid()];
          --ncount;
        }
        else {
          findChildren(child,nRes,ncount);
        }
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");
      map<long,int> nCount;
      int ntotal(0);
      for (const Particle& p: fs.particles()) {
        nCount[p.pid()] += 1;
        ++ntotal;
      }
      const FinalState& ufs = apply<FinalState>(event, "UFS");
      // loop over any chi mesons
      for (const Particle & chi : ufs.particles(Cuts::pid==20553 || Cuts::pid==555)) {
        if (chi.children().empty()) continue;
        map<long,int> nRes = nCount;
        int ncount = ntotal;
        findChildren(chi,nRes,ncount);
        // first check for 3 pi chi_b
        bool matched3Pi = false;
        if (ncount==3) {
          matched3Pi = true;
          for (const auto& val : nRes) {
            if (abs(val.first)==PID::PIPLUS || val.first==PID::PI0) {
              if (val.second!=1) {
                matched3Pi = false;
                break;
              }
            }
            else if (val.second!=0) {
              matched3Pi = false;
              break;
            }
          }
        }
        // then for omega chi_b
        bool matchedOmega = false;
        for(const Particle & omega : ufs.particles(Cuts::pid==223)) {
          Particle parent = omega;
          while (!parent.parents().empty()) {
            parent = parent.parents()[0];
            if (parent.pid()==555 || parent.pid()==20553) break;
          }
          if ((parent.pid()==555 || parent.pid()==20553) &&
               fuzzyEquals(parent.momentum(),chi.momentum())) continue;
          map<long,int> nRes2 = nRes;
          int ncount2 = ncount;
          findChildren(omega,nRes2,ncount2);
          matchedOmega = true;
          for(const auto& val : nRes2) {
            if (val.second!=0) {
              matchedOmega = false;
              break;
            }
          }
          if (matchedOmega) break;
        }
        if (!matched3Pi && !matchedOmega) continue;
        unsigned int iloc= chi.pid()==20553 ? 0 : 1;
        if (matched3Pi) {
          _h[0][iloc]->fill("10.867"s);
        }
        if (matchedOmega) {
          _h[1][iloc]->fill("10.867"s);
        }
        if (matched3Pi && !matchedOmega) {
          _h[2][iloc]->fill("10.867"s);
        }
        break;
      }
    }

    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix=0; ix<3; ++ix) {
        scale(_h[ix], crossSection()/ sumOfWeights() /picobarn);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _h[3][2];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BELLE_2014_I1309588);

}