Rivet analyses

Mass distributions in B → D*nπ decays

Experiment: BELLE (KEKB)

Inspire ID: 658085

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 70 (2004) 111103

Beams: * *

Beam energies: ANY

Run details: none listed

Measurement of mass distributions of the pions in the decays B → D*nπ, where all the pions are charged. The data were read from, the plots in the papers but are corrected for efficiency.

Source code:BELLE_2004_I658085.cc

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

namespace Rivet {


  /// @brief B -> D* + pions
  class BELLE_2004_I658085 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2004_I658085);


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

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 || Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(PID::PI0);
      BB.addStable(413);
      BB.addStable(-413);
      BB.addStable(423);
      BB.addStable(-423);
      BB.addStable(PID::PI0);
      declare(BB, "BB");
      for (unsigned int ix = 0; ix < 6; ++ix) book(_h[ix], 1, 1, 1 + ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // decay modes
      static const map<PdgId, unsigned int>& mode1 = {{-413, 1}, {211, 2}, {-211, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{413, 1}, {-211, 2}, {211, 1}};
      static const map<PdgId, unsigned int>& mode2 = {{-413, 1}, {211, 3}, {-211, 1}};
      static const map<PdgId, unsigned int>& mode2CC = {{413, 1}, {-211, 3}, {211, 1}};
      static const map<PdgId, unsigned int>& mode3 = {{-413, 1}, {211, 3}, {-211, 2}};
      static const map<PdgId, unsigned int>& mode3CC = {{413, 1}, {-211, 3}, {211, 2}};
      static const map<PdgId, unsigned int>& mode4 = {{-423, 1}, {211, 2}, {-211, 1}};
      static const map<PdgId, unsigned int>& mode4CC = {{423, 1}, {-211, 2}, {211, 1}};
      static const map<PdgId, unsigned int>& mode5 = {{-423, 1}, {211, 2}, {-211, 2}};
      static const map<PdgId, unsigned int>& mode5CC = {{423, 1}, {-211, 2}, {211, 2}};
      static const map<PdgId, unsigned int>& mode6 = {{-423, 1}, {211, 3}, {-211, 2}};
      static const map<PdgId, unsigned int>& mode6CC = {{423, 1}, {-211, 3}, {211, 2}};
      // loop over particles
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      int imode = -1;
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        int sign = BB.decaying()[ix].pid() / BB.decaying()[ix].abspid();
        if ((sign == 1 && BB.modeMatches(ix, 4, mode1)) || (sign == -1 && BB.modeMatches(ix, 4, mode1CC)))
          imode = 0;
        else if ((sign == 1 && BB.modeMatches(ix, 5, mode2))
                 || (sign == -1 && BB.modeMatches(ix, 5, mode2CC)))
          imode = 1;
        else if ((sign == 1 && BB.modeMatches(ix, 6, mode3))
                 || (sign == -1 && BB.modeMatches(ix, 6, mode3CC)))
          imode = 2;
        else if ((sign == 1 && BB.modeMatches(ix, 4, mode4))
                 || (sign == -1 && BB.modeMatches(ix, 4, mode4CC)))
          imode = 3;
        else if ((sign == 1 && BB.modeMatches(ix, 5, mode5))
                 || (sign == -1 && BB.modeMatches(ix, 5, mode5CC)))
          imode = 4;
        else if ((sign == 1 && BB.modeMatches(ix, 6, mode6))
                 || (sign == -1 && BB.modeMatches(ix, 6, mode6CC)))
          imode = 5;
        else
          continue;
        FourMomentum ptotal;
        for (const Particle& p : BB.decayProducts()[ix].at(sign * 211)) {
          ptotal += p.momentum();
        }
        for (const Particle& p : BB.decayProducts()[ix].at(-sign * 211)) {
          ptotal += p.momentum();
        }
        _h[imode]->fill(ptotal.mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 6; ++ix) normalize(_h[ix]);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[6];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2004_I658085);

}