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BELLE_2010_I871475

Mass distributions in $B^+\to J/\psi, \psi(2S) +K^+\pi^+\pi^-$
Experiment: BELLE (KEKB)
Inspire ID: 871475
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 83 (2011) 032005
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing B+ mesons, originally Upsilon(4S) decays

Measurement of mass distributions in the decays $B^+\to J/\psi, \psi(2S) +K^+\pi^+\pi^-$. The data were read from the plots in the paper and may not have been corrected for efficiency and resolution, although ther backgrounds given in the paper have been subtracted.

Source code: BELLE_2010_I871475.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
#include "Rivet/Tools/BinnedHistogram.hh"

namespace Rivet {


  /// @brief B+ -> J/psi/psi(2S) K+ pi+ pi-
  class BELLE_2010_I871475 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2010_I871475);


    /// @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(100443);
      BP.addStable(443);
      declare(BP, "BP");
      // histograms
      vector<double> bins[2] = {{0.60,1.46,2.32,3.18,4.04,4.90},
				{0.60,1.00,1.40,1.80,2.20,2.60}};
      for(unsigned int ix=0;ix<2;++ix) {
	book(_c[ix],"TMP/c_"+toString(ix+1));
	for(unsigned int iy=0;iy<3;++iy) {
	  book(_h_all[ix][iy],1+ix,1,1+iy);
	  if(iy>1) continue;
	  for(unsigned int iz=0;iz<5;++iz) {
	    Histo1DPtr tmp;
	    book(tmp,3+ix,1+iy,1+iz);
	    _h_slice[ix][iy].add(bins[ix][iz],bins[ix][iz+1],tmp);
	  }
	}
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode1   = { { 321,1}, { 211,1}, {-211,1}, {    443,1}};
      static const map<PdgId,unsigned int> & mode1CC = { {-321,1}, { 211,1}, {-211,1}, {    443,1}};
      static const map<PdgId,unsigned int> & mode2   = { { 321,1}, { 211,1}, {-211,1}, { 100443,1}};
      static const map<PdgId,unsigned int> & mode2CC = { {-321,1}, { 211,1}, {-211,1}, { 100443,1}};
      DecayedParticles BP = apply<DecayedParticles>(event, "BP");
      // loop over particles
      for(unsigned int ix=0;ix<BP.decaying().size();++ix) {
	int imode=-1, sign = 1;
	if (BP.decaying()[ix].pid()>0 && BP.modeMatches(ix,4,mode1)) {
	  sign=1;
	  imode=0;
	}
	else if  (BP.decaying()[ix].pid()<0 && BP.modeMatches(ix,4,mode1CC)) {
	  sign=-1;
	  imode=0;
	}
	else if (BP.decaying()[ix].pid()>0 && BP.modeMatches(ix,4,mode2)) {
	  sign=1;
	  imode=1;
	}
	else if  (BP.decaying()[ix].pid()<0 && BP.modeMatches(ix,4,mode2CC)) {
	  sign=-1;
	  imode=1;
	}
	else
	  continue;
      	const Particle & Kp  = BP.decayProducts()[ix].at( 321*sign)[0];
       	const Particle & pip = BP.decayProducts()[ix].at( 211*sign)[0];
       	const Particle & pim = BP.decayProducts()[ix].at(-211*sign)[0];
	double m2Kpipi = (Kp .momentum()+pip.momentum()+pim.momentum()).mass2();
	double m2Kpi   = (Kp .momentum()+pim.momentum()).mass2();
	double m2pipi  = (pip.momentum()+pim.momentum()).mass2();
	_h_all[imode][0]->fill(m2Kpipi);
	_h_all[imode][1]->fill(m2Kpi  );
	_h_all[imode][2]->fill(m2pipi );
	_h_slice[imode][0].fill(m2Kpipi,m2Kpi );
	_h_slice[imode][1].fill(m2Kpipi,m2pipi);
	_c[imode]->fill();
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<2;++ix) {
	for(unsigned int iy=0;iy<3;++iy) {
	  scale(_h_all[ix][iy],1./ *_c[ix]);
	  if(iy>1) continue;
	  for (Histo1DPtr histo : _h_slice[ix][iy].histos())
	    scale(histo, 1./ *_c[ix]);
	}
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_all[2][3];
    BinnedHistogram _h_slice[2][2];
    CounterPtr _c[2];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BELLE_2010_I871475);

}