Rivet analyses

Mass distributions in B0 → K+K−KS0, B+ → K+K−K+ and B+ → KS0KS0K+

Experiment: BABAR (PEP-II)

Inspire ID: 1086537

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 85 (2012) 112010

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0 and B+, originally Upsilon(4S) decays

Mass distributions in B0 → K+K−KS0, B+ → K+K−K+ and B+ → KS0KS0K+. The data were read from the plots in the paper.

Source code:BABAR_2012_I1086537.cc

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

namespace Rivet {


  /// @brief B -> K K K decays
  class BABAR_2012_I1086537 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2012_I1086537);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 or Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(310);
      declare(BB, "BB");
      // histograms
      for (unsigned int ix = 0; ix < 3; ++ix)
        for (unsigned int iy = 0; iy < 3; ++iy) book(_h_aver[ix][iy], 1 + 2 * ix, 1, 1 + iy);
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_charge2[ix], 4, 1, 1 + ix);
        for (unsigned int iy = 0; iy < 2; ++iy) book(_h_charge1[ix][iy], 2, 1 + iy, 1 + ix);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{321, 2}, {-321, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{321, 1}, {-321, 2}};
      static const map<PdgId, unsigned int>& mode2 = {{310, 2}, {321, 1}};
      static const map<PdgId, unsigned int>& mode2CC = {{310, 2}, {-321, 1}};
      static const map<PdgId, unsigned int>& mode3 = {{310, 1}, {321, 1}, {-321, 1}};
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        int sign = 1, imode = 0;
        if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode1)) {
          imode = 0;
          sign = 1;
        }
        else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode1CC)) {
          imode = 0;
          sign = -1;
        }
        else if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode2)) {
          imode = 1;
          sign = 1;
        }
        else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode2CC)) {
          imode = 1;
          sign = -1;
        }
        else if (BB.modeMatches(ix, 3, mode3)) {
          imode = 2;
          if (BB.decaying()[ix].pid() < 0) sign = -1;
        }
        else
          continue;
        // B+ -> K+ K+ K-
        if (imode == 0) {
          const Particles& Kp = BB.decayProducts()[ix].at(sign * 321);
          const Particle& Km = BB.decayProducts()[ix].at(-sign * 321)[0];
          double mKpKm[2];
          for (unsigned int ix = 0; ix < 2; ++ix) mKpKm[ix] = (Kp[ix].momentum() + Km.momentum()).mass();
          if (mKpKm[0] > mKpKm[1]) swap(mKpKm[0], mKpKm[1]);
          _h_aver[0][0]->fill(mKpKm[0]);
          _h_aver[0][1]->fill(mKpKm[1]);
          _h_aver[0][2]->fill((Kp[0].momentum() + Kp[1].momentum()).mass());
          if (BB.decaying()[ix].pid() > 0) {
            for (unsigned int ix = 0; ix < 2; ++ix) _h_charge1[0][ix]->fill(mKpKm[0]);
          }
          else {
            for (unsigned int ix = 0; ix < 2; ++ix) _h_charge1[1][ix]->fill(mKpKm[0]);
          }
        }
        // B+ -> KS0 KS0 K+
        else if (imode == 1) {
          const Particles& K0 = BB.decayProducts()[ix].at(310);
          const Particle& Kp = BB.decayProducts()[ix].at(sign * 321)[0];
          double mK0K0 = (K0[0].momentum() + K0[1].momentum()).mass();
          _h_aver[1][0]->fill(mK0K0);
          double mKpK0[2];
          for (unsigned int ix = 0; ix < 2; ++ix) mKpK0[ix] = (K0[ix].momentum() + Kp.momentum()).mass();
          if (mKpK0[0] > mKpK0[1]) swap(mKpK0[0], mKpK0[1]);
          _h_aver[1][1]->fill(mKpK0[1]);
          _h_aver[1][2]->fill(mKpK0[0]);
          if (BB.decaying()[ix].pid() > 0) {
            _h_charge2[0]->fill(mK0K0);
          }
          else {
            _h_charge2[1]->fill(mK0K0);
          }
        }
        // B0 -> KS0 K+ K-
        else if (imode == 2) {
          const Particle& K0 = BB.decayProducts()[ix].at(310)[0];
          const Particle& Kp = BB.decayProducts()[ix].at(sign * 321)[0];
          const Particle& Km = BB.decayProducts()[ix].at(-sign * 321)[0];
          _h_aver[2][0]->fill((Kp.momentum() + Km.momentum()).mass());
          _h_aver[2][1]->fill((K0.momentum() + Km.momentum()).mass());
          _h_aver[2][2]->fill((K0.momentum() + Kp.momentum()).mass());
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 3; ++ix)
        for (unsigned int iy = 0; iy < 3; ++iy) normalize(_h_aver[ix][iy], 1., false);
      for (unsigned int ix = 0; ix < 2; ++ix) {
        normalize(_h_charge2[ix], 1., false);
        for (unsigned int iy = 0; iy < 2; ++iy) normalize(_h_charge1[ix][iy], 1., false);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_aver[3][3];
    Histo1DPtr _h_charge1[2][2];
    Histo1DPtr _h_charge2[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2012_I1086537);

}