Rivet analyses

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

namespace Rivet {


  /// @brief e+e- > hyperons
  class BABAR_2007_I760730 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2007_I760730);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");
      book(_nLL, "/TMP/nLL" );
      book(_nSS, "/TMP/nSS" );
      book(_nLS, "/TMP/nLS" );
    }

    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");
      // total hadronic and muonic cross sections
      map<long,int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
    nCount[p.pid()] += 1;
    ++ntotal;
      }

      // find the Lambdas and Sigmas
      const FinalState& ufs = apply<UnstableParticles>(event, "UFS");
      for(unsigned int ix=0;ix<ufs.particles().size();++ix) {
        const Particle& p1 = ufs.particles()[ix];
        if(abs(p1.pid())!=3122&&abs(p1.pid())!=3212) continue;
        bool matched = false;
        // check fs
        bool fs = true;
        for(const Particle & child : p1.children()) {
          if(child.pid()==p1.pid()) {
            fs = false;
            break;
          }
        }
        if(!fs) continue;
        // find the children
        map<long,int> nRes = nCount;
        int ncount = ntotal;
        findChildren(p1,nRes,ncount);
        for(unsigned int iy=ix+1;iy<ufs.particles().size();++iy) {
          const Particle& p2 = ufs.particles()[iy];
      if(abs(p2.pid())!=3122&&abs(p2.pid())!=3212) continue;
      // check fs
      bool fs = true;
      for(const Particle & child : p2.children()) {
        if(child.pid()==p2.pid()) {
          fs = false;
          break;
        }
      }
      if(!fs) continue;
          map<long,int> nRes2 = nRes;
          int ncount2 = ncount;
          findChildren(p2,nRes2,ncount2);
          if(ncount2!=0) continue;
          matched=true;
          for(auto const & val : nRes2) {
            if(val.second!=0) {
              matched = false;
              break;
            }
          }
          if(matched) {
        if(abs(p1.pid())==3122 && abs(p2.pid())==3122)
          _nLL->fill();
        else if(abs(p1.pid())==3212 && abs(p2.pid())==3212)
          _nSS->fill();
        else
          _nLS->fill();
            break;
          }
        }
        if(matched) break;
      }
    }

    /// Normalise histograms etc., after the run
    void finalize() {
      double fact = crossSection()/ sumOfWeights() /picobarn;
      for(unsigned int ix=1;ix<4;++ix) {
    double sigma,error;
    if(ix==1) {
      sigma = _nLL->val()*fact;
      error = _nLL->err()*fact;
    }
    else if(ix==2) {
      sigma = _nSS->val()*fact;
      error = _nSS->err()*fact;
    }
    else {
      sigma = _nLS->val()*fact;
      error = _nLS->err()*fact;
    }
    Estimate1DPtr  mult;
        book(mult, ix, 1, 1);
    for (auto& b : mult->bins()) {
      if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
        b.set(sigma, error);
      }
    }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    CounterPtr _nLL,_nSS,_nLS;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BABAR_2007_I760730);


}