Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/ChargedFinalState.hh"

#define I_KNOW_THE_INITIAL_QUARKS_PROJECTION_IS_DODGY_BUT_NEED_TO_USE_IT
#include "Rivet/Projections/InitialQuarks.hh"

namespace Rivet {


  /// @brief Add a short analysis description here
  class DELPHI_1999_I448370 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_1999_I448370);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(Beam(), "Beams");
      declare(ChargedFinalState(), "FS");
      declare(InitialQuarks(), "IQF");

      // Book histograms
      book(_h_F_T, 1, 1, 1);
      book(_h_F_L, 2, 1, 1);
      book(_h_F_A, 3, 1, 1);
      book(_h_F_TL, 4, 1, 1);
      book(_h_F_T_total, 5, 1, 1);
      book(_h_F_L_total, 5, 1, 2);
      book(_h_F_TL_total, 5, 1, 3);
      book(_h_b_F_T, 7, 1, 1);
      book(_h_b_F_L, 7, 1, 2);
      book(_h_light_F_T, 8, 1, 1);
      book(_h_light_F_L, 8, 1, 2);
      book(_n_bottom, 9, 1, 1);
      book(_n_light, 9, 1, 2);

      book(_c_light, "/TMP/wLight");
      book(_c_bottom, "/TMP/wBottom");
      book(_c_total, "/TMP/wTotal");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // First, veto on leptonic events by requiring at least 4 charged FS particles
      const FinalState& fs = apply<FinalState>(event, "FS");
      const size_t numParticles = fs.particles().size();

      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
      if (numParticles < 2) {
        MSG_DEBUG("Failed leptonic event cut");
        vetoEvent;
      }
      MSG_DEBUG("Passed leptonic event cut");

      int flavour = 0;
      const InitialQuarks& iqf = apply<InitialQuarks>(event, "IQF");

      // If we only have two quarks (qqbar), just take the flavour.
      // If we have more than two quarks, look for the highest energetic q-qbar pair.
      if (iqf.particles().size() == 2) {
        flavour = iqf.particles().front().abspid();
      }
      else {
        map<int, double> quarkmap;
        for (const Particle& p : iqf.particles()) {
          if (quarkmap[p.pid()] < p.E()) {
            quarkmap[p.pid()] = p.E();
          }
        }
        double maxenergy = 0.;
        for (int i = 1; i <= 5; ++i) {
          if (quarkmap[i] + quarkmap[-i] > maxenergy) {
            flavour = i;
          }
        }
      }
      if (flavour == 5)
        _c_bottom->fill();
      else if (flavour != 4)
        _c_light->fill();
      _c_total->fill();
      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double meanBeamMom = (beams.first.p3().mod() + beams.second.p3().mod()) / 2.0;
      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
      Vector3 axis;
      if (beams.first.pid() > 0) {
        axis = beams.first.momentum().p3().unit();
      }
      else {
        axis = beams.second.momentum().p3().unit();
      }

      // loop over charged particles
      double v = 0.8, v2 = sqr(v), v5 = v2 * v2 * v;
      for (const Particle& p : fs.particles()) {
        double xp = p.p3().mod() / meanBeamMom;
        double ctheta = axis.dot(p.momentum().p3().unit());
        if (abs(ctheta) < 0.8) {
          double WT = 0.5 / v5 * (5. * sqr(ctheta) * (3. - v2) - v2 * (5. - 3. * v2));
          double WL = 0.25 / v5 * (v2 * (5. + 3. * v2) - 5. * sqr(ctheta) * (3. + v2));
          double WA = 2. * ctheta / v2 / v;
          _h_F_T->fill(xp, WT);
          _h_F_L->fill(xp, WL);
          _h_F_TL->fill(xp, (WL + WT));
          _h_F_T_total->fill(xp, 0.5 * xp * WT);
          _h_F_L_total->fill(xp, 0.5 * xp * WL);
          _h_F_TL_total->fill(xp, 0.5 * xp * (WL + WT));
          if (p.charge() > 0) {
            _h_F_A->fill(xp, WA);
          }
          else {
            _h_F_A->fill(xp, -WA);
          }
          if (flavour == 5) {
            _h_b_F_T->fill(xp, WT);
            _h_b_F_L->fill(xp, WL);
          }
          else if (flavour != 4) {
            _h_light_F_T->fill(xp, WT);
            _h_light_F_L->fill(xp, WL);
          }
        }
      }

      if (flavour == 5) {
        _n_bottom->fill(Ecm, fs.particles().size());
      }
      else if (flavour != 4) {
        _n_light->fill(Ecm, fs.particles().size());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_F_T, 1. / *_c_total);
      scale(_h_F_L, 1. / *_c_total);
      scale(_h_F_A, 1. / *_c_total);
      scale(_h_F_TL, 1. / *_c_total);
      {
        Estimate1DPtr temp;
        divide(_h_F_L, _h_F_T, book(temp, 6, 1, 1));
      }
      {
        Estimate1DPtr temp;
        divide(_h_F_L, _h_F_TL, book(temp, 6, 1, 2));
      }
      scale(_h_F_T_total, 1. / *_c_total);
      scale(_h_F_L_total, 1. / *_c_total);
      scale(_h_F_TL_total, 1. / *_c_total);
      scale(_h_b_F_T, 1. / *_c_bottom);
      scale(_h_b_F_L, 1. / *_c_bottom);
      scale(_h_light_F_T, 1. / *_c_light);
      scale(_h_light_F_L, 1. / *_c_light);
      scale(_n_bottom, 1. / *_c_bottom);
      scale(_n_light, 1. / *_c_light);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_F_T, _h_F_L, _h_F_A, _h_F_TL, _h_b_F_T, _h_b_F_L, _h_light_F_T, _h_light_F_L;
    Histo1DPtr _h_F_T_total, _h_F_L_total, _h_F_TL_total;
    BinnedHistoPtr<string> _n_light, _n_bottom;
    CounterPtr _c_light, _c_bottom, _c_total;
    const string Ecm = "91.2";
    /// @}
  };


  RIVET_DECLARE_PLUGIN(DELPHI_1999_I448370);


}