Rivet analyses

Mass distributions in the decay B̄⁰ → Λ_c⁺p̄π⁺π⁻

Experiment: BABAR (PEP-II)

Inspire ID: 1217425

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 87 (2013) 9, 092004

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0/Bbar0, original e+e- at Upsilon(4S)

Measurements of mass distributions in B̄⁰ → Λ_c⁺p̄π⁺π⁻ and modes with intermediate states. The data were read from the plots in the paper but are background subtracted and efficiency corrected.

Source code:`BABAR_2013_I1217425.cc`

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

namespace Rivet {


  /// @brief Bbar0 -> Lambda_c+ pbar pi+ pi-
  class BABAR_2013_I1217425 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2013_I1217425);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid==511);
      declare(ufs, "UFS");
      DecayedParticles B0(ufs);
      // treat Lambda_c, Sigma_c and sigma_c* as stable
      B0.addStable( 4122);
      B0.addStable(-4122);
      B0.addStable( 4112);
      B0.addStable(-4112);
      B0.addStable( 4212);
      B0.addStable(-4212);
      B0.addStable( 4222);
      B0.addStable(-4222);
      B0.addStable( 4114);
      B0.addStable(-4114);
      B0.addStable( 4214);
      B0.addStable(-4214);
      B0.addStable( 4224);
      B0.addStable(-4224);
      declare(B0, "B0");
      // histograms
      for(unsigned int ix=0;ix<5;++ix) {
    for(unsigned int iy=0;iy<6;++iy) {
      if( (ix<3 && iy>=3) or (ix==4 && iy>=4) ) continue;
      book(_h[ix][iy],1+ix,1,1+iy);
    }
      }
    }

    
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode1   = { { 4112,1},{-2212,1}, { 211,1}};
      static const map<PdgId,unsigned int> & mode1CC = { {-4112,1},{ 2212,1}, {-211,1}};
      static const map<PdgId,unsigned int> & mode2   = { { 4222,1},{-2212,1}, {-211,1}};
      static const map<PdgId,unsigned int> & mode2CC = { {-4222,1},{ 2212,1}, { 211,1}};
      static const map<PdgId,unsigned int> & mode3   = { { 4224,1},{-2212,1}, {-211,1}};
      static const map<PdgId,unsigned int> & mode3CC = { {-4224,1},{ 2212,1}, { 211,1}};
      static const map<PdgId,unsigned int> & mode4   = { { 4122,1},{-2212,1}, { 211,1}, {-211,1}};
      static const map<PdgId,unsigned int> & mode4CC = { {-4122,1},{ 2212,1}, { 211,1}, {-211,1}};
      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
      // loop over particles
      for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
    int sign = 1,imode=-1, ibaryon,ipi=-211;
    if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,mode1)) {
      sign=1;
      imode=0;
      ibaryon=4112;
      ipi=211;
    }
    else if  (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode1CC)) {
      sign=-1;
      imode=0;
      ibaryon=4112;
      ipi=211;
    }
    else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,mode2)) {
      sign=1;
      imode=1;
      ibaryon=4222;
    }
    else if  (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode2CC)) {
      sign=-1;
      imode=1;
      ibaryon=4222;
    }
    else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,mode3)) {
      sign=1;
      imode=2;
      ibaryon=4224;
    }
    else if  (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode3CC)) {
      sign=-1;
      imode=2;
      ibaryon=4224;
    }
    else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,4,mode4)) {
      sign=1;
      imode=3;
      ibaryon=4122;
    }
    else if  (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,4,mode4CC)) {
      sign=-1;
      imode=3;
      ibaryon=4122;
    }
    else
      continue;
    const Particle & SigC = B0.decayProducts()[ix].at( sign*ibaryon)[0];
        const Particle & pbar = B0.decayProducts()[ix].at(-sign*2212   )[0];
        const Particle & pim  = B0.decayProducts()[ix].at( sign*ipi    )[0];
    if(imode<=2) {
      _h[imode][0]->fill((SigC.momentum()+pim .momentum()).mass());
      _h[imode][1]->fill((SigC.momentum()+pbar.momentum()).mass());
      _h[imode][2]->fill((pbar.momentum()+pim .momentum()).mass());
    }
    else {
      const Particle & pip  = B0.decayProducts()[ix].at(-sign*ipi    )[0];
      _h[imode][0]->fill((SigC.momentum()+pip .momentum()).mass());
      _h[imode][1]->fill((SigC.momentum()+pim .momentum()).mass());
      _h[imode][2]->fill((pbar.momentum()+pip .momentum()).mass());
      _h[imode][3]->fill((pbar.momentum()+pim .momentum()).mass());
      FourMomentum ppipi = pip .momentum()+pim .momentum();
      _h[imode][4]->fill(ppipi.mass());
      FourMomentum plam = SigC.momentum()+pbar.momentum();
      _h[imode][5]->fill(plam.mass());
      _h[4][0]->fill((ppipi+pbar.momentum()).mass());
      _h[4][1]->fill((ppipi+SigC.momentum()).mass());
      _h[4][2]->fill((plam+pim.momentum()).mass());
      _h[4][3]->fill((plam+pip.momentum()).mass());
    }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<5;++ix) {
    for(unsigned int iy=0;iy<6;++iy) {
      if( (ix<3 && iy>=3) or (ix==4 && iy>=5) ) continue;
      normalize(_h[ix][iy],1.,false);
    }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[5][6];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BABAR_2013_I1217425);

}

Rivet analyses

Mass distributions in the decay B̄0 → Λc+p̄π+π−

Source code:BABAR_2013_I1217425.cc

Mass distributions in the decay B̄⁰ → Λ_c⁺p̄π⁺π⁻

Source code:`BABAR_2013_I1217425.cc`