Rivet analyses

Ds(*)−K+ mass distribution in B+ → Ds(*)−K+π+ decays

Experiment: BELLE (KEKB)

Inspire ID: 816632

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 80 (2009) 052005

Beams: * *

Beam energies: ANY

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

Measurement of the Ds(*)−K+ mass distribution in B+ → Ds(*)−K+π+ decays. The data were read from the plots in the paper and may not be corrected for efficiency/acceptance, although the backgrounds given wre subtracted.

Source code:BELLE_2009_I816632.cc

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

namespace Rivet {


  /// @brief B+ -> D_s(*) K pi
  class BELLE_2009_I816632 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2009_I816632);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BP(ufs);
      BP.addStable(431);
      BP.addStable(-431);
      BP.addStable(433);
      BP.addStable(-433);
      declare(BP, "BP");
      // histograms
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_mass[ix], 1, 1, 1 + ix);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{-431, 1}, {321, 1}, {211, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{431, 1}, {-321, 1}, {-211, 1}};
      static const map<PdgId, unsigned int>& mode2 = {{-433, 1}, {321, 1}, {211, 1}};
      static const map<PdgId, unsigned int>& mode2CC = {{433, 1}, {-321, 1}, {-211, 1}};
      DecayedParticles BP = apply<DecayedParticles>(event, "BP");
      // loop over particles
      for (unsigned int ix = 0; ix < BP.decaying().size(); ++ix) {
        int sign = 1, mode = 0;
        if (BP.modeMatches(ix, 3, mode1)) {
          mode = 0;
          sign = 1;
        }
        else if (BP.modeMatches(ix, 3, mode1CC)) {
          sign = -1;
          mode = 0;
        }
        else if (BP.modeMatches(ix, 3, mode2)) {
          mode = 1;
          sign = 1;
        }
        else if (BP.modeMatches(ix, 3, mode2CC)) {
          sign = -1;
          mode = 1;
        }
        else
          continue;
        const Particle& Ds = BP.decayProducts()[ix].at(-sign * (431 + 2 * mode))[0];
        const Particle& Kp = BP.decayProducts()[ix].at(sign * 321)[0];
        _h_mass[mode]->fill((Ds.momentum() + Kp.momentum()).mass());
      }
    }


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

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_mass[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2009_I816632);

}