Rivet analyses

K−KS0 mass distribution in B → D(*)K−KS0 decays

Experiment: BELLE (KEKB)

Inspire ID: 2655951

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 2305.01321

Beams: * *

Beam energies: ANY

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

Measurement of K−KS0 mass distribution in B → D(*)K−KS0 decays. The corrected, background subtracted data was read from the figures in the paper.

Source code:BELLE_2023_I2655951.cc

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

namespace Rivet {


  /// @brief  B -> D(*) K- KS0
  class BELLE_2023_I2655951 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2023_I2655951);


    /// @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 < 4; ++ix) {
        book(_h[ix], 1, 1, 1 + ix);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const double mDs = 1.96835;
      static const map<PdgId, unsigned int> modes[4] = {{{-421, 1}, {321, 1}, {310, 1}},
                                                        {{-411, 1}, {321, 1}, {310, 1}},
                                                        {{-423, 1}, {321, 1}, {310, 1}},
                                                        {{-413, 1}, {321, 1}, {310, 1}}};
      static const map<PdgId, unsigned int> modesCC[4] = {{{421, 1}, {-321, 1}, {310, 1}},
                                                          {{411, 1}, {-321, 1}, {310, 1}},
                                                          {{423, 1}, {-321, 1}, {310, 1}},
                                                          {{413, 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 < 4; ++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();
        const Particle& Km = BB.decayProducts()[ix].at(sign * 321)[0];
        const Particle& K0 = BB.decayProducts()[ix].at(310)[0];
        double mKK = (Km.momentum() + K0.momentum()).mass();
        if (abs(mKK - mDs) < 0.02) continue;
        _h[imode]->fill(mKK);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h, 1.0, false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[4];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2023_I2655951);

}