1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/ChargedFinalState.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief e+ e- > hadrons near Upsilon resonances
10  class ARGUS_1994_I375418 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1994_I375418);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22
23      // Initialise and register projections
24      declare(FinalState(), "FS");
25      declare(ChargedFinalState(), "CFS");
26
27      // Book histograms
28      for(unsigned int ix=0;ix<3;++ix)
29        book(_sigma[ix], 1+ix,1,1);
30      _eCent = getOption<string>("ECENT", std::to_string(sqrtS()/MeV));
31    }
32
33
34    /// Perform the per-event analysis
35    void analyze(const Event& event) {
36      if (apply<ChargedFinalState>(event,"CFS").particles().size()<3) vetoEvent;
37      const FinalState& fs = apply<FinalState>(event, "FS");
38      map<long,int> nCount;
39      int ntotal(0);
40      for (const Particle& p : fs.particles()) {
41        nCount[p.pid()] += 1;
42        ++ntotal;
43      }
44      // mu+mu- + photons
45      if (nCount[-13]==1 and nCount[13]==1 && ntotal==2+nCount[22]) {
46        vetoEvent;
47      }
48      else if (nCount[-11]==1 and nCount[11]==1 && ntotal==2+nCount[22]) {
49        vetoEvent;
50      }
51      else { // everything else
52        _sigma[0]->fill(_eCent);
53        _sigma[1]->fill(_eCent);
54        double H0=0.,H2=0;
55        for (unsigned int ix=0; ix<fs.particles().size(); ++ix) {
56          double p1 = fs.particles()[ix].p3().mod();
57          for (unsigned int iy=0; iy<fs.particles().size(); ++iy) {
58            double p2 = fs.particles()[iy].p3().mod();
59            double cTheta=fs.particles()[ix].p3().dot(fs.particles()[iy].p3())/p1/p2;
60            double pre=p1*p2/s;
61            H0 += pre;
62            H2 += 0.5*pre*(3.*sqr(cTheta)-1);
63          }
64        }
65        if (H2/H0<0.35) _sigma[2]->fill(_eCent);
66      }
67    }
68
69
70    /// Normalise histograms etc., after the run
71    void finalize() {
72      scale(_sigma, crossSection()/sumOfWeights()/nanobarn);
73    }
74
75    /// @}
76
77
78    /// @name Histograms
79    /// @{
80    BinnedHistoPtr<string> _sigma[3];
81    string _eCent;
82    /// @}
83
84
85  };
86
87
88  RIVET_DECLARE_PLUGIN(ARGUS_1994_I375418);
89
90}