Rivet analyses

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

namespace Rivet {


  /// @brief B -> D(*) K K(*)
  class BELLE_2002_I590700 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2002_I590700);


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

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 or Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(411);
      BB.addStable(-411);
      BB.addStable(421);
      BB.addStable(-421);
      BB.addStable(413);
      BB.addStable(-413);
      BB.addStable(423);
      BB.addStable(-423);
      BB.addStable(310);
      BB.addStable(313);
      BB.addStable(-313);
      declare(BB, "BB");
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_mass[ix], 1 + 2 * ix, 1, 1);
        for (unsigned int iy = 0; iy < 2; ++iy) {
          book(_h_angle[ix][iy], 2, 1 + iy, 1 + ix);
        }
      }
      book(_h_angle[2][0], 3, 2, 1);
    }

    bool isK(int pid) const {
      return pid == 130 || pid == 310 || pid == 311 || pid == 321;
    }

    bool isPi(int pid) const {
      return pid == 211 || pid == 111;
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const double mDs = 1.96835;
      static const map<PdgId, unsigned int> modes[5] = {{{-421, 1}, {321, 1}, {-313, 1}},
                                                        {{-411, 1}, {321, 1}, {-313, 1}},
                                                        {{-423, 1}, {321, 1}, {-313, 1}},
                                                        {{-413, 1}, {321, 1}, {-313, 1}},
                                                        {{-421, 1}, {321, 1}, {310, 1}}};
      static const map<PdgId, unsigned int> modesCC[5] = {{{421, 1}, {-321, 1}, {313, 1}},
                                                          {{411, 1}, {-321, 1}, {313, 1}},
                                                          {{423, 1}, {-321, 1}, {313, 1}},
                                                          {{413, 1}, {-321, 1}, {313, 1}},
                                                          {{421, 1}, {-321, 1}, {310, 1}}};
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        int imode = -1;
        for (unsigned int iy = 0; iy < 5; ++iy) {
          if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, modes[iy])) {
            imode = iy;
            break;
          }
          else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, modesCC[iy])) {
            imode = iy;
            break;
            ;
          }
        }
        if (imode < 0) continue;
        int sign = BB.decaying()[ix].pid() / BB.decaying()[ix].abspid();
        LorentzTransform boostB = LorentzTransform::mkFrameTransformFromBeta(
            BB.decaying()[ix].mom().betaVec());
        if (imode < 4) {
          const Particle& Km = BB.decayProducts()[ix].at(sign * 321)[0];
          const Particle& K0 = BB.decayProducts()[ix].at(-sign * 313)[0];
          FourMomentum pKK = boostB.transform(Km.mom() + K0.mom());
          const double mKK = pKK.mass();
          if (abs(mKK - mDs) < 0.02) continue;
          _h_mass[0]->fill(mKK);
          LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pKK.betaVec());
          FourMomentum pK0 = boost2.transform(boostB.transform(K0.mom()));
          _h_angle[imode / 2][0]->fill(pK0.p3().unit().dot(pKK.p3().unit()));
          // find Kstar decay products
          Particle KK;
          if (isK(K0.children()[0].abspid()) && isPi(K0.children()[1].abspid())) {
            KK = K0.children()[0];
          }
          else if (isK(K0.children()[1].abspid()) && isPi(K0.children()[0].abspid())) {
            KK = K0.children()[1];
          }
          else {
            continue;
          }
          LorentzTransform boost3 = LorentzTransform::mkFrameTransformFromBeta(pK0.betaVec());
          FourMomentum pK = boost3.transform(boost2.transform(boostB.transform(KK.mom())));
          _h_angle[imode / 2][1]->fill(pKK.p3().unit().dot(pK0.p3().unit()));
        }
        else {
          const Particle& Km = BB.decayProducts()[ix].at(sign * 321)[0];
          const Particle& K0 = BB.decayProducts()[ix].at(310)[0];
          FourMomentum pKK = boostB.transform(Km.mom() + K0.mom());
          const double mKK = pKK.mass();
          if (abs(mKK - mDs) < 0.02) continue;
          _h_mass[1]->fill(mKK);
          LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pKK.betaVec());
          FourMomentum pK0 = boost2.transform(boostB.transform(K0.mom()));
          _h_angle[2][0]->fill(pK0.p3().unit().dot(pKK.p3().unit()));
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 2; ++ix) {
        normalize(_h_mass[ix], 1.0, false);
        for (unsigned int iy = 0; iy < 2; ++iy) {
          normalize(_h_angle[ix][iy], 1.0, false);
        }
      }
      normalize(_h_angle[2][0], 1., false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_mass[2], _h_angle[3][2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2002_I590700);

}