Rivet analyses

Mass distributions in B → pp̄K(*)

Experiment: BABAR (PEP-II)

Inspire ID: 755548

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 76 (2007) 092004

Beams: * *

Beam energies: ANY

Run details: none listed

Measurement of mass distributions in B0 → pp̄KS0, B0 → pp̄K*0, B+ → pp̄K+ and B+ → pp̄K*+. The corrected data were read from the plots in the paper.

Source code:BABAR_2007_I755548.cc

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

namespace Rivet {


  /// @brief  B -> p pbar meson
  class BABAR_2007_I755548 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2007_I755548);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid==511 ||
                        Cuts::abspid==521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable( 310);
      BB.addStable( 313);
      BB.addStable( 323);
      BB.addStable(-313);
      BB.addStable(-323);
      BB.addStable(   441);
      BB.addStable(   443);
      BB.addStable(100443);
      BB.addStable( 10441);
      BB.addStable( 20443);
      BB.addStable(   445);
      declare(BB, "BB");
      // histograms
      for(unsigned int ix=0;ix<4;++ix) {
    book(_h_mass[ix],1,1,1+ix);
    book(_c[ix],"TMP/c_"+toString(ix+1));
    for(unsigned int iy=0;iy<2;++iy)
      if(!(ix==0&&iy==1)) book(_h_mass2[iy][ix],2,1+iy,1+ix);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode1   = { { 2212,1}, {-2212,1}, { 310,1} };
      static const map<PdgId,unsigned int> & mode1CC = { { 2212,1}, {-2212,1}, { 310,1} };
      static const map<PdgId,unsigned int> & mode2   = { { 2212,1}, {-2212,1}, { 321,1} };
      static const map<PdgId,unsigned int> & mode2CC = { { 2212,1}, {-2212,1}, {-321,1} };
      static const map<PdgId,unsigned int> & mode3   = { { 2212,1}, {-2212,1}, { 313,1} };
      static const map<PdgId,unsigned int> & mode3CC = { { 2212,1}, {-2212,1}, {-313,1} };
      static const map<PdgId,unsigned int> & mode4   = { { 2212,1}, {-2212,1}, { 323,1} };
      static const map<PdgId,unsigned int> & mode4CC = { { 2212,1}, {-2212,1}, {-323,1} };
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      // loop over particles
      for(unsigned int ix=0;ix<BB.decaying().size();++ix) {
    int sign = BB.decaying()[ix].pid()/BB.decaying()[ix].abspid();
    int imode=-1, iK;
    if((sign>0 &&BB.modeMatches(ix,3,mode1)) ||
       (sign<0 &&BB.modeMatches(ix,3,mode1CC))) {
      imode = 0;
      iK = 310;
    }
    else if((sign>0 &&BB.modeMatches(ix,3,mode2)) ||
        (sign<0 &&BB.modeMatches(ix,3,mode2CC))) {
      imode = 1;
      iK = sign*321;
    }
    else if((sign>0 &&BB.modeMatches(ix,3,mode3)) ||
        (sign<0 &&BB.modeMatches(ix,3,mode3CC))) {
      imode = 2;
      iK = sign*313;
    }
    else if((sign>0 &&BB.modeMatches(ix,3,mode4)) ||
        (sign<0 &&BB.modeMatches(ix,3,mode4CC))) {
      imode = 3;
      iK = sign*323;
    }
    else continue;
    _c[imode]->fill();
    const Particle & pp    = BB.decayProducts()[ix].at( sign*2212)[0];
    const Particle & pbar  = BB.decayProducts()[ix].at(-sign*2212)[0];
    const Particle & meson = BB.decayProducts()[ix].at(        iK)[0];
    FourMomentum pbaryon = pp.momentum()+pbar.momentum();
    double mass = pbaryon.mass();
    _h_mass[imode]->fill(mass);
    double mph[2] = {(pp  .momentum()+meson.momentum()).mass(),
             (pbar.momentum()+meson.momentum()).mass()};
    if(imode==0) {
      _h_mass2[0][imode]->fill(max(mph[0],mph[1]));
    }
    else {
      if(mph[0]>mph[1])
        _h_mass2[0][imode]->fill(mph[0]);
      else 
        _h_mass2[1][imode]->fill(mph[1]);
    }
      }
    }

    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<4;++ix) {
    normalize(_h_mass[ix],1.,false);
    for(unsigned int iy=0;iy<2;++iy)
      if(_h_mass2[iy][ix]) scale(_h_mass2[iy][ix],1./ *_c[ix]);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_mass[4],_h_mass2[2][4];
    CounterPtr _c[4];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2007_I755548);

}