Rivet analyses

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

namespace Rivet {


  /// @brief gamma gamma -> omega phi, omega omega and phi phi
  class BELLE_2012_I1090664 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2012_I1090664);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(Cuts::pid == 223 || Cuts::pid == 333), "UFS");
      // counters
      for (unsigned int ix = 0; ix < 3; ++ix) {
        for (unsigned int iy = 0; iy < 2; ++iy) {
          book(_sigma[ix][iy], "TMP/c_" + toString(ix + 1) + "_" + toString(iy + 1),
               refData(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()] -= 1;
          --ncount;
        }
        else {
          findChildren(child, nRes, ncount);
        }
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");
      // find the final-state particles
      map<long, int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
        nCount[p.pid()] += 1;
        ++ntotal;
      }
      // find any rho mesons
      Particles mesons = apply<UnstableParticles>(event, "UFS").particles();
      for (unsigned int ix = 0; ix < mesons.size(); ++ix) {
        if (mesons[ix].children().empty()) continue;
        map<long, int> nRes = nCount;
        int ncount = ntotal;
        findChildren(mesons[ix], nRes, ncount);
        bool matched = false;
        for (unsigned int iy = ix + 1; iy < mesons.size(); ++iy) {
          if (mesons[iy].children().empty()) continue;
          map<long, int> nRes2 = nRes;
          int ncount2 = ncount;
          findChildren(mesons[iy], nRes2, ncount2);
          if (ncount2 != 0) continue;
          matched = true;
          for (const auto& val : nRes2) {
            if (val.second != 0) {
              matched = false;
              break;
            }
          }
          if (matched) {
            if (mesons[ix].pid() != mesons[iy].pid()) {
              for (unsigned int iy = 0; iy < 2; ++iy) {
                _sigma[0][iy]->fill(sqrtS());
              }
            }
            else if (mesons[ix].pid() == 333) {
              for (unsigned int iy = 0; iy < 2; ++iy) {
                _sigma[1][iy]->fill(sqrtS());
              }
            }
            else if (mesons[ix].pid() == 223) {
              for (unsigned int iy = 0; iy < 2; ++iy) {
                _sigma[2][iy]->fill(sqrtS());
              }
            }
            break;
          }
        }
        if (matched) break;
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      const double fact = crossSection() / nanobarn / sumOfWeights();
      // loop over tables in paper
      for (unsigned int ix = 0; ix < 3; ++ix) {
        for (unsigned int iy = 0; iy < 2; ++iy) {
          scale(_sigma[ix][iy], fact);
          Estimate1DPtr tmp;
          book(tmp, 1, ix + 1, 1 + iy);
          barchart(_sigma[ix][iy], tmp);
        }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _sigma[3][2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2012_I1090664);

}