1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/ChargedFinalState.hh"
 5#include "Rivet/Projections/UnstableParticles.hh"
 6#include "Rivet/Projections/Beam.hh"
 7
 8namespace Rivet {
 9
10
11  /// @brief A Measurement of K*+- (892) production in hadronic Z0 decays
12  /// @author Simone Amoroso
13  class OPAL_1993_I342766 : public Analysis {
14  public:
15
16    /// Constructor
17    RIVET_DEFAULT_ANALYSIS_CTOR(OPAL_1993_I342766);
18
19
20    /// @name Analysis methods
21    /// @{
22
23    /// Book histograms and initialise projections before the run
24    void init() {
25      // Initialise and register projections
26      declare(Beam(), "Beams");
27      declare(ChargedFinalState(), "FS");
28      declare(UnstableParticles(), "UFS");
29      // Book histograms
30      book(_histXeKStar892, 1, 1, 1);
31      book(_histMeanKStar892, 2, 1, 1);
32    }
33
34
35    /// Perform the per-event analysis
36    void analyze(const Event& event) {
37
38      const FinalState& fs = apply<FinalState>(event, "FS");
39      const size_t numParticles = fs.particles().size();
40
41      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
42      if (numParticles < 2) {
43        MSG_DEBUG("Failed leptonic event cut");
44        vetoEvent;
45      }
46      MSG_DEBUG("Passed leptonic event cut");
47
48      // Get beams and average beam momentum
49      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
50      const double meanBeamMom = 0.5*(beams.first.p3().mod() + beams.second.p3().mod());
51      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
52
53      // Final state of unstable particles to get particle spectra
54      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
55
56      for (const Particle& p : ufs.particles(Cuts::abspid==323)) {
57        const double xp = p.p3().mod()/meanBeamMom;
58        _histXeKStar892->fill(xp);
59        _histMeanKStar892->fill(Ecm);
60      }
61    }
62
63
64    /// Normalise histograms etc., after the run
65    void finalize() {
66      scale(_histXeKStar892, 1./sumOfWeights());
67      scale(_histMeanKStar892, 1./sumOfWeights());
68    }
69
70    /// @}
71
72
73  private:
74
75    /// @name Histograms
76    Histo1DPtr _histXeKStar892;
77    BinnedHistoPtr<string> _histMeanKStar892;
78    const string Ecm = "91.2";
79
80  };
81
82
83
84  RIVET_DECLARE_PLUGIN(OPAL_1993_I342766);
85
86
87}