1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/FastJets.hh"
 5#include "Rivet/Projections/LeptonFinder.hh"
 6#include "Rivet/Projections/MissingMomentum.hh"
 7#include "Rivet/Projections/DirectFinalState.hh"
 8#include "Rivet/Projections/UnstableParticles.hh"
 9
10namespace Rivet {
11
12
13  /// @brief direct photon spectrum in upslion decay
14  class CRYSTAL_BALL_1991_I315873 : public Analysis {
15  public:
16
17    /// Constructor
18    RIVET_DEFAULT_ANALYSIS_CTOR(CRYSTAL_BALL_1991_I315873);
19
20
21    /// @name Analysis methods
22    /// @{
23
24    /// Book histograms and initialise projections before the run
25    void init() {
26      // projections
27      declare(UnstableParticles(), "UFS");
28      book(_h_gamma[0],2,1,1);
29      book(_h_gamma[1],2,1,2);
30    }
31
32
33    /// Perform the per-event analysis
34    void analyze(const Event& event) {
35      // Find the Upsilons among the unstables
36      for (const Particle& ups : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==553)) {
37	unsigned int nhadron(0);
38	Particles photons;
39	for(const Particle & child : ups.children()) {
40	  if(PID::isHadron(child.pid()))
41	    ++nhadron;
42	  else if(child.pid()==PID::PHOTON)
43	    photons.push_back(child);
44	}
45	if(nhadron!=0 && !photons.empty()) {
46	  LorentzTransform boost;
47	  if (ups.p3().mod() > 1*MeV)
48	    boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
49	  for(const Particle & gamma:photons) {
50	    double z = 2.*boost.transform(gamma.momentum()).E()/ups.mass();
51	    _h_gamma[0]->fill(z);
52	    _h_gamma[1]->fill(z);
53	  }
54	}
55      }
56    }
57
58
59    /// Normalise histograms etc., after the run
60    void finalize() {
61      normalize(_h_gamma[0],1.,false);
62      normalize(_h_gamma[1],1.,false);
63    }
64
65    /// @}
66
67
68    /// @name Histograms
69    /// @{
70    Histo1DPtr _h_gamma[2];
71    /// @}
72
73
74  };
75
76
77  RIVET_DECLARE_PLUGIN(CRYSTAL_BALL_1991_I315873);
78
79}