Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"
#include "fastjet/JadePlugin.hh"

namespace fastjet {

  class P_scheme : public JetDefinition::Recombiner {
  public:

    std::string description() const {
      return "";
    }
    void recombine(const PseudoJet& pa, const PseudoJet& pb, PseudoJet& pab) const {
      PseudoJet tmp = pa + pb;
      double E = sqrt(tmp.px() * tmp.px() + tmp.py() * tmp.py() + tmp.pz() * tmp.pz());
      pab.reset_momentum(tmp.px(), tmp.py(), tmp.pz(), E);
    }
    void preprocess(PseudoJet& p) const {
      double E = sqrt(p.px() * p.px() + p.py() * p.py() + p.pz() * p.pz());
      p.reset_momentum(p.px(), p.py(), p.pz(), E);
    }
    ~P_scheme() { }
  };

  class E0_scheme : public JetDefinition::Recombiner {
  public:

    std::string description() const {
      return "";
    }
    void recombine(const PseudoJet& pa, const PseudoJet& pb, PseudoJet& pab) const {
      PseudoJet tmp = pa + pb;
      double fact = tmp.E() / sqrt(tmp.px() * tmp.px() + tmp.py() * tmp.py() + tmp.pz() * tmp.pz());
      pab.reset_momentum(fact * tmp.px(), fact * tmp.py(), fact * tmp.pz(), tmp.E());
    }
    void preprocess(PseudoJet& p) const {
      double fact = p.E() / sqrt(p.px() * p.px() + p.py() * p.py() + p.pz() * p.pz());

      p.reset_momentum(fact * p.px(), fact * p.py(), fact * p.pz(), p.E());
    }
    ~E0_scheme() { }
  };

}


namespace Rivet {


  /// @brief AMY jets at
  class AMY_1995_I406129 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(AMY_1995_I406129);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      FinalState fs;
      declare(fs, "FS");
      // Book histograms
      book(_h["jade_P"], 2, 1, 1);
      book(_h["jade_E"], 3, 1, 1);
      book(_h["jade_E0"], 6, 1, 1);
      book(_h["durham"], 4, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      Particles particles = apply<FinalState>(event, "FS").particles();
      MSG_DEBUG("Num particles = " << particles.size());
      PseudoJets pjs;
      double mpi = .13957;
      for (const Particle& p : particles) {
        Vector3 mom = p.p3();
        double energy = p.E();
        if (PID::isCharged(p.pid())) {
          energy = sqrt(mom.mod2() + sqr(mpi));
        }
        else {
          double fact = energy / mom.mod();
          mom *= fact;
        }
        pjs.push_back(fastjet::PseudoJet(mom.x(), mom.y(), mom.z(), energy));
      }
      // durham
      fastjet::JetDefinition durDef(fastjet::ee_kt_algorithm, fastjet::E_scheme);
      fastjet::ClusterSequence durham(pjs, durDef);
      double y_23 = durham.exclusive_ymerge_max(2);
      size_t idx = durhamAxis.index(y_23);
      string label = idx > 0 && idx <= _h["durham"]->xEdges().size() ? _h["durham"]->xEdges()[idx - 1]
                                                                     : "OTHER";
      _h["durham"]->fill(label);
      // jade e-scheme
      fastjet::JetDefinition::Plugin* plugin = new fastjet::JadePlugin();
      fastjet::JetDefinition jadeEDef(plugin);
      jadeEDef.set_recombination_scheme(fastjet::E_scheme);
      fastjet::ClusterSequence jadeE(pjs, jadeEDef);
      y_23 = jadeE.exclusive_ymerge_max(2);
      idx = jadeAxis.index(y_23);
      label = idx > 0 && idx <= _h["jade_E"]->xEdges().size() ? _h["jade_E"]->xEdges()[idx - 1] : "OTHER";
      _h["jade_E"]->fill(label);
      // jade p-scheme
      fastjet::P_scheme p_scheme;
      fastjet::JetDefinition jadePDef(plugin);
      jadePDef.set_recombiner(&p_scheme);
      fastjet::ClusterSequence jadeP(pjs, jadePDef);
      y_23 = jadeP.exclusive_ymerge_max(2);
      idx = jadeAxis.index(y_23);
      label = idx > 0 && idx <= _h["jade_P"]->xEdges().size() ? _h["jade_P"]->xEdges()[idx - 1] : "OTHER";
      _h["jade_P"]->fill(label);
      // jade E0-scheme
      fastjet::E0_scheme e0_scheme;
      fastjet::JetDefinition jadeE0Def(plugin);
      jadeE0Def.set_recombiner(&e0_scheme);
      fastjet::ClusterSequence jadeE0(pjs, jadeE0Def);
      y_23 = jadeE0.exclusive_ymerge_max(2);
      idx = jadeAxis.index(y_23);
      label = idx > 0 && idx <= _h["jade_E0"]->xEdges().size() ? _h["jade_E0"]->xEdges()[idx - 1] : "OTHER";
      _h["jade_E0"]->fill(label);
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h, 1. / sumOfWeights());
      for (auto& hist : _h) {
        for (auto& b : hist.second->bins()) {
          const size_t idx = b.index();
          b.scaleW(hist.first == "durham" ? 1. / durhamAxis.width(idx) : 1. / jadeAxis.width(idx));
        }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    map<string, BinnedHistoPtr<string>> _h;
    YODA::Axis<double> jadeAxis{0.0, 0.01, 0.02, 0.03, 0.04,   0.05, 0.06, 0.07, 0.0825,
                                0.1, 0.12, 0.14, 0.16, 0.1825, 0.21, 0.24, 0.27, 0.3};
    YODA::Axis<double> durhamAxis{0.0,    0.002, 0.004, 0.0065, 0.0115, 0.02,   0.03, 0.04, 0.05, 0.06, 0.07,
                                  0.0825, 0.1,   0.12,  0.14,   0.16,   0.1825, 0.21, 0.24, 0.27, 0.3};
    /// @}
  };


  RIVET_DECLARE_PLUGIN(AMY_1995_I406129);


}