Rivet analyses

Hadronic mass distributions in B → D(*)π(π)ℓν decays

Experiment: BELLE (KEKB)

Inspire ID: 2512112

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 2211.09833

Beams: * *

Beam energies: ANY

Run details: - Any process produding b0 and B+, originally Upsilon(4S) decay

Measurement of the mass of the hadronic system in B → D(*)π(π)ℓν decays

Source code:BELLE_2022_I2512112.cc

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

namespace Rivet {


  /// @brief B -> D pi (pi) semileptonic
  class BELLE_2022_I2512112 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2022_I2512112);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      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(PID::PI0);
      declare(BB, "BB");
      // histograms
      for(unsigned int ix=0;ix<3;++ix)
    for(unsigned int iy=0;iy<2;++iy)
      book(_h[ix][iy],1+ix,1,1+iy);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> mode1[4] = {{ {-421,1}, {-211,1}, {-11,1}, { 12,1}},
                               { { 421,1}, { 211,1}, { 11,1}, {-12,1}},
                               { {-421,1}, {-211,1}, {-13,1}, { 14,1}},
                               { { 421,1}, { 211,1}, { 13,1}, {-14,1}}};
      static const map<PdgId,unsigned int> mode2[4] = {{ {-411,1}, { 211,1}, {-11,1}, { 12,1}},
                               { { 411,1}, {-211,1}, { 11,1}, {-12,1}},
                               { {-411,1}, { 211,1}, {-13,1}, { 14,1}},
                               { { 411,1}, {-211,1}, { 13,1}, {-14,1}}};
      static const map<PdgId,unsigned int> mode3[4] = {{ {-423,1}, {-211,1}, {-11,1}, { 12,1}},
                               { { 423,1}, { 211,1}, { 11,1}, {-12,1}},
                               { {-423,1}, {-211,1}, {-13,1}, { 14,1}},
                               { { 423,1}, { 211,1}, { 13,1}, {-14,1}}};
      static const map<PdgId,unsigned int> mode4[4] = {{ {-413,1}, { 211,1}, {-11,1}, { 12,1}},
                               { { 413,1}, {-211,1}, { 11,1}, {-12,1}},
                               { {-413,1}, { 211,1}, {-13,1}, { 14,1}},
                               { { 413,1}, {-211,1}, { 13,1}, {-14,1}}};
      static const map<PdgId,unsigned int> mode5[4] = {{ {-411,1}, {-211,1}, { 211,1}, {-11,1}, { 12,1}},
                               { { 411,1}, {-211,1}, { 211,1}, { 11,1}, {-12,1}},
                               { {-411,1}, {-211,1}, { 211,1}, {-13,1}, { 14,1}},
                               { { 411,1}, {-211,1}, { 211,1}, { 13,1}, {-14,1}}};
      static const map<PdgId,unsigned int> mode6[4] = {{ {-421,1}, {-211,1}, { 211,1}, {-11,1}, { 12,1}},
                               { { 421,1}, {-211,1}, { 211,1}, { 11,1}, {-12,1}},
                               { {-421,1}, {-211,1}, { 211,1}, {-13,1}, { 14,1}},
                               { { 421,1}, {-211,1}, { 211,1}, { 13,1}, {-14,1}}};
      // loop over B mesons
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      // loop over particles
      for(unsigned int ix=0;ix<BB.decaying().size();++ix) {
    for(unsigned int il=0;il<4;++il) {
      int iD,iloc1,iloc2;
      if ( BB.modeMatches(ix,4,mode1[il]) ) {
        iloc1=0;
        iloc2=0;
        iD=-421;
      }
      else if ( BB.modeMatches(ix,4,mode2[il]) ) {
        iloc1=0;
        iloc2=1;
        iD=-411;
      }
      else if ( BB.modeMatches(ix,4,mode3[il]) ) {
        iloc1=1;
        iloc2=0;
        iD=-423;
      }
      else if ( BB.modeMatches(ix,4,mode4[il]) ) {
        iloc1=1;
        iloc2=1;
        iD=-413;
      }
      else if ( BB.modeMatches(ix,5,mode5[il]) ) {
        iloc1=2;
        iloc2=0;
        iD=-411;
      }
      else if ( BB.modeMatches(ix,5,mode6[il]) ) {
        iloc1=2;
        iloc2=1;
        iD=-421;
      }
      else continue;
      int sign = il%2==0 ? 1 : -1;
      int ipi = -sign*211;
      if(iloc2==1) ipi *=-1;
      const Particle & pi1= BB.decayProducts()[ix].at( ipi)[0];
      const Particle & DD = BB.decayProducts()[ix].at( iD*sign )[0];
      FourMomentum pHad = pi1.momentum()+DD.momentum();
      if(iloc1==2) {
        const Particle & pi2= BB.decayProducts()[ix].at(-ipi)[0];
        pHad += pi2.momentum();
      }
      double mass = pHad.mass();
      if(iloc1==1) mass -=DD.mass();
      _h[iloc1][iloc2]->fill(mass);
    }
      }
    }


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

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[3][2];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BELLE_2022_I2512112);

}