1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// @brief gamma gamma -> rho+ rho-
 10  class ARGUS_1989_I266416 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1989_I266416);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      // Initialise and register projections
 23      declare(FinalState(), "FS");
 24      declare(UnstableParticles(), "UFS");
 25      // book histos
 26      if (inRange(sqrtS()/GeV,0.8,3.4)) {
 27        for (unsigned int ix=0; ix<4; ++ix) {
 28          book(_nMeson[ix],"TMP/nMeson_"+toString(ix+1));
 29        }
 30      }
 31      else {
 32        throw Error("Invalid CMS energy for ARGUS_1989_I266416");
 33      }
 34    }
 35
 36    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 37      for (const Particle &child : p.children()) {
 38        if (child.children().empty()) {
 39          nRes[child.pid()]-=1;
 40          --ncount;
 41        }
 42        else {
 43          findChildren(child,nRes,ncount);
 44        }
 45      }
 46    }
 47
 48    /// Perform the per-event analysis
 49    void analyze(const Event& event) {
 50      const FinalState& fs = apply<FinalState>(event, "FS");
 51      // find the final-state particles
 52      map<long,int> nCount;
 53      int ntotal(0);
 54      for (const Particle& p : fs.particles()) {
 55        nCount[p.pid()] += 1;
 56        ++ntotal;
 57      }
 58      bool foundRes=false;
 59      // find any rho mesons
 60      Particles rho=apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==213);
 61      for (unsigned int ix=0;ix<rho.size();++ix) {
 62       	if(rho[ix].children().empty()) continue;
 63       	map<long,int> nRes=nCount;
 64       	int ncount = ntotal;
 65       	findChildren(rho[ix],nRes,ncount);
 66        bool matched = false;
 67        for (unsigned int iy=ix+1;iy<rho.size();++iy) {
 68          if(rho[iy].children().empty()) continue;
 69          if(rho[ix].pid()!=-rho[iy].pid()) continue;
 70          map<long,int> nRes2=nRes;
 71          int ncount2 = ncount;
 72          findChildren(rho[iy],nRes2,ncount2);
 73          if(ncount2 !=0 ) continue;
 74          matched=true;
 75          for (auto const& val : nRes2) {
 76            if (val.second!=0) {
 77              matched = false;
 78              break;
 79            }
 80          }
 81          if (matched) {
 82            break;
 83          }
 84        }
 85        if (matched) {
 86          _nMeson[1]->fill();
 87          foundRes=true;
 88          break;
 89        }
 90        else {
 91          int sign = rho[ix].pid()/rho[ix].abspid();
 92          bool matched2=true;
 93          for (const auto& val : nRes) {
 94            if (val.first==-sign*211 || val.first==111) {
 95              if (val.second!=1) {
 96                matched2 = false;
 97                break;
 98              }
 99            }
100            else {
101              if (val.second!=0) {
102                matched2 = false;
103                break;
104              }
105            }
106          }
107          if (matched2) {
108            _nMeson[2]->fill();
109            foundRes=true;
110            break;
111          }
112        }
113      }
114      // 4 pion final-state
115      if (ntotal==4) {
116        if (nCount[PID::PIPLUS]==1 && nCount[PID::PIMINUS]==1 && nCount[PID::PI0]==2) {
117          _nMeson[0]->fill();
118          if (!foundRes) _nMeson[3]->fill();
119        }
120      }
121    }
122
123
124    /// Normalise histograms etc., after the run
125    void finalize() {
126      scale(_nMeson, crossSection()/nanobarn/sumOfWeights());
127      // loop over tables in paper
128      for (unsigned int ix=0; ix<4; ++ix) {
129        BinnedEstimatePtr<string> mult;
130        book(mult, ix+1, 1, 1);
131        for (auto& b : mult->bins()) {
132          if (isCompatibleWithSqrtS(std::stod(b.xEdge())/GeV)) {
133            b.setVal(_nMeson[ix]->val());
134            b.setErr(_nMeson[ix]->err());
135          }
136        }
137      }
138    }
139
140    /// @}
141
142
143    /// @name Histograms
144    /// @{
145    CounterPtr _nMeson[4];
146    /// @}
147
148
149  };
150
151
152  RIVET_DECLARE_PLUGIN(ARGUS_1989_I266416);
153
154}