Rivet analyses

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

namespace Rivet {


  /// @brief e+e- > omega pi0, K* Kbar K2 Kbar
  class BELLE_2013_I1252555 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2013_I1252555);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");

      // counters
      for (size_t ix = 0; ix < 5; ++ix) {
        book(_sigma[ix], 1 + ix, 1, 1);
      }
      for (const string& en : _sigma[0].binning().edges<0>()) {
        const double eval = stod(en);
        if (isCompatibleWithSqrtS(eval)) {
          _sqs = en;
          break;
        }
      }
      raiseBeamErrorIf(_sqs.empty());
    }

    void findChildren(const Particle& p, map<long, int>& nRes, int& ncount) const {
      for (const Particle& child : p.children()) {
        if (child.children().empty()) {
          nRes[child.pid()] -= 1;
          --ncount;
        }
        else {
          findChildren(child, nRes, ncount);
        }
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // final state particles
      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;
      }
      // resonances
      for (const Particle& p :
           apply<UnstableParticles>(event, "UFS")
               .particles(Cuts::abspid == 223 || Cuts::abspid == 313 || Cuts::abspid == 323
                          || Cuts::abspid == 315 || Cuts::abspid == 325)) {
        map<long, int> nRes = nCount;
        int ncount = ntotal;
        findChildren(p, nRes, ncount);
        if (ncount != 1) continue;
        unsigned int imode = 0;
        long pid = 111;
        if (p.abspid() == 313) {
          imode = 1;
          pid = 310;
        }
        else if (p.abspid() == 323) {
          imode = 2;
          pid = p.pid() > 0 ? -321 : 321;
        }
        else if (p.abspid() == 315) {
          imode = 3;
          pid = 310;
        }
        else if (p.abspid() == 325) {
          imode = 4;
          pid = p.pid() > 0 ? -321 : 321;
        }
        bool matched = true;
        for (const auto& val : nRes) {
          if ((pid == 310 && (val.first == 310 || val.second == 130)) || val.first == pid) {
            if (val.second != 1) {
              matched = false;
              break;
            }
          }
          else if (val.second != 0) {
            matched = false;
            break;
          }
        }
        if (matched) {
          _sigma[imode]->fill(_sqs);
          break;
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_sigma, crossSection() / sumOfWeights() / femtobarn);
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _sigma[5];
    string _sqs = "";
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2013_I1252555);

}