Rivet analyses

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

namespace Rivet {


  /// @brief B -> K* l+l-
  class BABAR_2016_I1391152 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2016_I1391152);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 || Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(443);
      BB.addStable(100443);
      BB.addStable(313);
      BB.addStable(323);
      BB.addStable(-313);
      BB.addStable(-323);
      declare(BB, "BB");
      // book histograms
      for (unsigned int ix = 0; ix < 2; ++ix) {
        for (unsigned int iy = 0; iy < 3; ++iy) {
          book(_p_FL[ix][iy], 1, 1 + ix, 1 + iy);
          book(_p_FB[ix][iy], 2, 1 + ix, 1 + iy);
          book(_p_P2_num[ix][iy], "TMP/P2_num_" + toString(ix + 1) + "_" + toString(iy + 1),
               refData(3, 1 + ix, 1 + iy));
          book(_p_P2_den[ix][iy], "TMP/P2_den_" + toString(ix + 1) + "_" + toString(iy + 1),
               refData(3, 1 + ix, 1 + iy));
        }
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{323, 1}, {13, 1}, {-13, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{-323, 1}, {13, 1}, {-13, 1}};
      static const map<PdgId, unsigned int>& mode2 = {{313, 1}, {13, 1}, {-13, 1}};
      static const map<PdgId, unsigned int>& mode2CC = {{-313, 1}, {13, 1}, {-13, 1}};
      static const map<PdgId, unsigned int>& mode3 = {{323, 1}, {11, 1}, {-11, 1}};
      static const map<PdgId, unsigned int>& mode3CC = {{-323, 1}, {11, 1}, {-11, 1}};
      static const map<PdgId, unsigned int>& mode4 = {{313, 1}, {11, 1}, {-11, 1}};
      static const map<PdgId, unsigned int>& mode4CC = {{-313, 1}, {11, 1}, {-11, 1}};
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      // loop over particles
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        int imode = 0;
        if ((BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode1))
            || (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode1CC)))
          imode = 0;
        else if ((BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode2))
                 || (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode2CC)))
          imode = 1;
        else if ((BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode3))
                 || (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode3CC)))
          imode = 2;
        else if ((BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode4))
                 || (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode4CC)))
          imode = 3;
        else
          continue;
        int il = imode < 2 ? 13 : 11;
        int sign = BB.decaying()[ix].pid() > 0 ? 1 : -1;
        const Particle& lp = BB.decayProducts()[ix].at(-sign * il)[0];
        const Particle& lm = BB.decayProducts()[ix].at(sign * il)[0];
        double qq = (lp.momentum() + lm.momentum()).mass2();
        int iK = BB.decaying()[ix].abspid() == 521 ? 323 : 313;
        iK *= BB.decaying()[ix].pid() / BB.decaying()[ix].abspid();
        const Particle& Kstar = BB.decayProducts()[ix].at(iK)[0];
        if (Kstar.children().size() != 2) continue;
        Particle KK;
        if (Kstar.abspid() == 313) {
          if (Kstar.children()[0].abspid() == 321 && Kstar.children()[1].abspid() == 211)
            KK = Kstar.children()[0];
          else if (Kstar.children()[1].abspid() == 321 && Kstar.children()[0].abspid() == 211)
            KK = Kstar.children()[1];
          else
            continue;
        }
        else {
          if (Kstar.children()[0].abspid() == 311 && Kstar.children()[1].abspid() == 211)
            KK = Kstar.children()[0];
          else if (Kstar.children()[1].abspid() == 311 && Kstar.children()[0].abspid() == 211)
            KK = Kstar.children()[1];
          else if (Kstar.children()[0].abspid() == 310 && Kstar.children()[1].abspid() == 211)
            KK = Kstar.children()[0];
          else if (Kstar.children()[1].abspid() == 310 && Kstar.children()[0].abspid() == 211)
            KK = Kstar.children()[1];
          else if (Kstar.children()[0].abspid() == 321 && Kstar.children()[1].abspid() == 111 && il == 11)
            KK = Kstar.children()[0];
          else if (Kstar.children()[1].abspid() == 321 && Kstar.children()[0].abspid() == 111 && il == 11)
            KK = Kstar.children()[1];
          else
            continue;
          if (KK.abspid() == 311) {
            if (KK.children().size() == 1 && KK.children()[0].pid() == 310)
              KK = KK.children()[0];
            else
              continue;
          }
        }
        // first boost to bottom frame
        const LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(
            BB.decaying()[ix].momentum().betaVec());
        FourMomentum plp = boost.transform(lp.momentum());
        FourMomentum plm = boost.transform(lm.momentum());
        FourMomentum pKstar = boost.transform(Kstar.momentum());
        FourMomentum pK = boost.transform(KK.momentum());
        FourMomentum pB = boost.transform(BB.decaying()[ix].momentum());
        // lepton stuff
        const LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta((plp + plm).betaVec());
        plp = boost2.transform(plp);
        double cTheta = plp.p3().unit().dot(boost.transform(pB).p3().unit());
        double AFB = cTheta > 0 ? 1 : -1;
        // kaon stuff
        const LorentzTransform boost3 = LorentzTransform::mkFrameTransformFromBeta(pKstar.betaVec());
        pK = boost3.transform(pK);
        cTheta = pK.p3().unit().dot(boost.transform(pB).p3().unit());
        double FL = .5 * (5. * sqr(cTheta) - 1.);
        // fill histograms
        for (unsigned int iz = 0; iz < 2; ++iz) {
          for (unsigned int iy = 0; iy < 3; ++iy) {
            if ((BB.decaying()[ix].abspid() == 511 && iy == 0)
                || (BB.decaying()[ix].abspid() == 521 && iy == 1))
              continue;
            _p_FB[iz][iy]->fill(qq, AFB);
            _p_FL[iz][iy]->fill(qq, FL);
            _p_P2_num[iz][iy]->fill(qq, -2. / 3. * AFB);
            _p_P2_den[iz][iy]->fill(qq, 1. - FL);
          }
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 2; ++ix) {
        for (unsigned int iy = 0; iy < 3; ++iy) {
          Estimate1DPtr tmp;
          book(tmp, 3, 1 + ix, 1 + iy);
          divide(_p_P2_num[ix][iy], _p_P2_den[ix][iy], tmp);
        }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Profile1DPtr _p_FL[2][3], _p_FB[2][3], _p_P2_num[2][3], _p_P2_den[2][3];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2016_I1391152);

}