Rivet analyses

title: BELLE_2002_I590700

Mass and angular distributions in $B\to D^{()}K^-K^{0()}$ decays

Experiment: BELLE (KEKB)

Inspire ID: 590700

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 542 (2002) 171-182

Beams: * *

Beam energies: ANY

Run details: - Any process producing B mesons, originally Upsilon(4S) decays

Measurement of mass and angular distributions in $B\to D^{()}K^-K^{0()}$ decays. The corrected, background subtracted data was read from the figures in the paper.

Source code:BELLE_2002_I590700.cc

```c++ // -- 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);

} ```