Rivet analyses

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

namespace Rivet {


  /// @brief Upsilon -> gamma pi+pi- K+K- ppbar
  class CLEOIII_2006_I694170 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOIII_2006_I694170);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 553);
      declare(ufs, "UFS");
      DecayedParticles UPS(ufs);
      declare(UPS, "UPS");
      declare(Beam(), "Beams");
      // histos
      for (unsigned int ix = 0; ix < 4; ++ix) {
        book(_h_mass[ix], 1 + ix, 1, 1);
      }
      for (unsigned int ix = 0; ix < 2; ++ix) {
        for (unsigned int iy = 0; iy < 2; ++iy) {
          book(_h_angle[ix][iy], 5 + ix, 1, 1 + iy);
        }
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // get the axis, direction of incoming electron
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      Vector3 axis;
      if (beams.first.pid() > 0) {
        axis = beams.first.momentum().p3().unit();
      }
      else {
        axis = beams.second.momentum().p3().unit();
      }
      unsigned int iprod[3] = {211, 321, 2212};
      const map<PdgId, unsigned int> modes[3] = {{{211, 1}, {-211, 1}, {22, 1}},
                                                 {{321, 1}, {-321, 1}, {22, 1}},
                                                 {{2212, 1}, {-2212, 1}, {22, 1}}};
      DecayedParticles UPS = apply<DecayedParticles>(event, "UPS");
      if (UPS.decaying().size() != 1) vetoEvent;
      int imode = -1;
      for (unsigned int ix = 0; ix < 3; ++ix) {
        if (UPS.modeMatches(0, 3, modes[ix])) {
          imode = ix;
          break;
        }
      }
      if (imode < 0) vetoEvent;
      const Particle& Mp = UPS.decayProducts()[0].at(iprod[imode])[0];
      const Particle& Mm = UPS.decayProducts()[0].at(-iprod[imode])[0];
      FourMomentum pMM = Mp.momentum() + Mm.momentum();
      double mass = pMM.mass();
      if (imode == 0) {
        _h_mass[0]->fill(mass);
        _h_mass[1]->fill(mass);
      }
      else {
        _h_mass[1 + imode]->fill(mass);
      }
      if (imode == 2) return;
      bool hasf2[2] = {false, false};
      for (const Particle& p : UPS.decaying()[0].children()) {
        if (p.pid() == 225)
          hasf2[0] = true;
        else if (p.pid() == 335)
          hasf2[1] = true;
      }
      if ((imode == 0 && hasf2[0]) || (imode == 1 && hasf2[1])) {
        const Particle& gam = UPS.decayProducts()[0].at(22)[0];
        const double cTheta = axis.dot(gam.p3().unit());
        _h_angle[imode][1]->fill(abs(cTheta));
        // remaining angles
        LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(
            UPS.decaying()[0].mom().betaVec());
        FourMomentum pGamma = boost1.transform(gam.mom());
        pMM = boost1.transform(pMM);
        Vector3 e1z = pGamma.p3().unit();
        LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pMM.betaVec());
        Vector3 axis2 = boost2.transform(boost1.transform(Mp.mom())).p3().unit();
        _h_angle[imode][0]->fill(abs(e1z.dot(axis2)));
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 4; ++ix) {
        normalize(_h_mass[ix], 1.0, false);
      }
      for (unsigned int ix = 0; ix < 2; ++ix) {
        for (unsigned int iy = 0; iy < 2; ++iy) {
          normalize(_h_angle[ix][iy], 1.0, false);
        }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_mass[4], _h_angle[2][2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(CLEOIII_2006_I694170);

}