1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/Beam.hh"
 4#include "Rivet/Projections/ChargedFinalState.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief BELLE pion and kaon continuum production
10  /// @author Peter Richardson
11  class BELLE_2013_I1216515 : public Analysis {
12  public:
13
14    BELLE_2013_I1216515()
15      : Analysis("BELLE_2013_I1216515")
16    { }
17
18
19    void analyze(const Event& e) {
20      // Loop through charged FS particles and look for charmed mesons/baryons
21      const ChargedFinalState& fs = apply<ChargedFinalState>(e, "FS");
22
23      const Beam beamproj = apply<Beam>(e, "Beams");
24      const ParticlePair& beams = beamproj.beams();
25      const FourMomentum mom_tot = beams.first.momentum() + beams.second.momentum();
26      const LorentzTransform cms_boost = LorentzTransform::mkFrameTransformFromBeta(mom_tot.betaVec());
27      MSG_DEBUG("CMS energy sqrt s = " << beamproj.sqrtS());
28
29      for (const Particle& p : fs.particles()) {
30        // energy in CMS frame
31        const double en = cms_boost.transform(p.momentum()).t();
32	const double z = 2.*en/beamproj.sqrtS();
33        const int PdgId = p.abspid();
34        MSG_DEBUG("pdgID = " << PdgId << "  Energy = " << en);
35        switch (PdgId) {
36	case PID::PIPLUS:
37	  _histPion->fill(z);
38	  break;
39	case PID::KPLUS:
40	  _histKaon->fill(z);
41	  break;
42	default :
43	  break;
44        }
45      }
46    } // analyze
47
48
49    void finalize() {
50
51      scale(_histPion,crossSection()/femtobarn/sumOfWeights());
52      scale(_histKaon,crossSection()/femtobarn/sumOfWeights());
53    } // finalize
54
55
56    void init() {
57      declare(Beam(), "Beams");
58      declare(ChargedFinalState(), "FS");
59
60      book(_histPion ,1,1,1);
61      book(_histKaon ,1,1,2);
62
63    } // init
64
65  private:
66
67    /// @{
68    // Histograms for continuum data (sqrt(s) = 10.52 GeV)
69    Histo1DPtr _histPion;
70    Histo1DPtr _histKaon;
71    /// @}
72
73  };
74
75
76  RIVET_DECLARE_PLUGIN(BELLE_2013_I1216515);
77
78}