Rivet analyses

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

namespace Rivet {


  /// @brief B -> p pbar K or p Lambdabar pi
  class BELLE_2005_I679165 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2005_I679165);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 || Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(310);
      BB.addStable(3122);
      BB.addStable(-3122);
      declare(BB, "BB");
      // histograms
      for (unsigned int ix = 0; ix < 4; ++ix) {
        book(_h_angle[ix], 2, 1, 1 + ix);
        if (ix == 3) continue;
        book(_h_mass[ix], 1, 1, 1 + ix);
      }
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_c[ix], "TMP/nB_" + toString(ix + 1));
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      // loop over particles
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        int sign = BB.decaying()[ix].pid() / BB.decaying()[ix].abspid();
        int imode = -1;
        if (BB.decaying()[ix].abspid() == 511)
          _c[0]->fill();
        else
          _c[1]->fill();
        if ((sign > 0 && BB.modeMatches(ix, 3, mode1)) || (sign < 0 && BB.modeMatches(ix, 3, mode1CC)))
          imode = 0;
        else if ((sign > 0 && BB.modeMatches(ix, 3, mode2)) || (sign < 0 && BB.modeMatches(ix, 3, mode2CC)))
          imode = 1;
        else if ((sign > 0 && BB.modeMatches(ix, 3, mode3)) || (sign < 0 && BB.modeMatches(ix, 3, mode3CC)))
          imode = 2;
        else {
          continue;
        }
        // boost to B rest frame
        LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(
            BB.decaying()[ix].mom().betaVec());
        if (imode < 2) {
          const Particle& pp = BB.decayProducts()[ix].at(sign * 2212)[0];
          const Particle& pbar = BB.decayProducts()[ix].at(-sign * 2212)[0];
          const Particle& meson = BB.decayProducts()[ix].at(imode == 0 ? sign * 321 : 310)[0];
          FourMomentum pbaryon = pp.mom() + pbar.mom();
          double mass = pbaryon.mass();
          if (2.850 < mass && mass < 3.12) continue;
          if (3.315 < mass && mass < 3.735) continue;
          _h_mass[imode]->fill(mass);
          if (mass > 2.85) continue;
          FourMomentum pp1 = boost.transform(pp.mom());
          pbaryon = boost.transform(pbaryon);
          Vector3 axis = boost.transform(meson.mom()).p3().unit();
          LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(pbaryon.betaVec());
          double cosp = axis.dot(boost1.transform(pp1).p3().unit());
          _h_angle[imode]->fill(cosp);
        }
        else {
          const Particle& pp = BB.decayProducts()[ix].at(sign * 2212)[0];
          const Particle& lbar = BB.decayProducts()[ix].at(-sign * 3122)[0];
          const Particle& meson = BB.decayProducts()[ix].at(-sign * 211)[0];
          FourMomentum pbaryon = pp.mom() + lbar.mom();
          double mass = pbaryon.mass();
          _h_mass[imode]->fill(mass);
          FourMomentum pp1 = boost.transform(pp.mom());
          FourMomentum pppi = pp.mom() + meson.mom();
          LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pppi.betaVec());
          Vector3 axis = boost.transform(lbar.mom()).p3().unit();
          double cosp = axis.dot(boost2.transform(pp1).p3().unit());
          _h_angle[3]->fill(cosp);
          if (mass > 2.85) continue;
          pbaryon = boost.transform(pbaryon);
          axis = boost.transform(meson.mom()).p3().unit();
          LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(pbaryon.betaVec());
          cosp = axis.dot(boost1.transform(pp1).p3().unit());
          _h_angle[imode]->fill(cosp);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_mass[0], 1e6 / *_c[1]);
      scale(_h_mass[1], 1e6 / *_c[0]);
      scale(_h_mass[2], 1e6 / *_c[0]);
      scale(_h_angle[0], 1e6 / *_c[1]);
      for (unsigned int ix = 1; ix < 4; ++ix) {
        scale(_h_angle[ix], 1e6 / *_c[0]);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_mass[3], _h_angle[4];
    CounterPtr _c[2];
    const map<PdgId, unsigned int> mode1 = {{2212, 1}, {-2212, 1}, {321, 1}};
    const map<PdgId, unsigned int> mode1CC = {{2212, 1}, {-2212, 1}, {-321, 1}};
    const map<PdgId, unsigned int> mode2 = {{2212, 1}, {-2212, 1}, {310, 1}};
    const map<PdgId, unsigned int> mode2CC = {{2212, 1}, {-2212, 1}, {310, 1}};
    const map<PdgId, unsigned int> mode3 = {{2212, 1}, {-3122, 1}, {-211, 1}};
    const map<PdgId, unsigned int> mode3CC = {{-2212, 1}, {3122, 1}, {211, 1}};
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2005_I679165);

}