Rivet analyses

Mass distributions in Λc+ → Σ+K+K− and Λc+ → Λ0KS0K+

Experiment: BELLE (KEKB)

Inspire ID: 566127

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 524 (2002) 33-43

Beams: * *

Beam energies: ANY

Run details: none listed

Mass distributions in Λc+ → Σ+K+K− and Λc+ → Λ0KS0K+. The data were read from the plots in the paper and are not corrected. The background given was subtracted. The statistics are fairly low, however these are the only distributions available for these modes.

Source code:BELLE_2002_I566127.cc

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

namespace Rivet {


  /// @brief Lambda_c decays
  class BELLE_2002_I566127 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2002_I566127);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid==4122);
      declare(ufs, "UFS");
      DecayedParticles LAMBDAC(ufs);
      LAMBDAC.addStable(PID::PI0);
      LAMBDAC.addStable(PID::K0S);
      LAMBDAC.addStable( 3122);
      LAMBDAC.addStable(-3122);
      LAMBDAC.addStable( 3222);
      LAMBDAC.addStable(-3222);
      declare(LAMBDAC, "LAMBDAC");
      // histos
      for (unsigned int ix=0;ix<3;++ix) {
        book(_h[ix],1+ix,1,1);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      DecayedParticles LAMBDAC = apply<DecayedParticles>(event, "LAMBDAC");
      // loop over particles
      for (unsigned int ix=0;ix<LAMBDAC.decaying().size();++ix) {
        int sign = LAMBDAC.decaying()[ix].pid()/LAMBDAC.decaying()[ix].abspid();
        if ((LAMBDAC.decaying()[ix].pid()>0 && LAMBDAC.modeMatches(ix,3,mode1  )) ||
            (LAMBDAC.decaying()[ix].pid()<0 && LAMBDAC.modeMatches(ix,3,mode1CC))) {
          const Particle& sig = LAMBDAC.decayProducts()[ix].at( sign*3222)[0];
          const Particle& Kp  = LAMBDAC.decayProducts()[ix].at( sign*321 )[0];
          const Particle& Km  = LAMBDAC.decayProducts()[ix].at(-sign*321 )[0];
          _h[0]->fill((Kp .mom()+Km.mom()).mass());
          _h[1]->fill((sig.mom()+Km.mom()).mass());
        }
        else if ((LAMBDAC.decaying()[ix].pid()>0 && LAMBDAC.modeMatches(ix,3,mode2)) ||
                 (LAMBDAC.decaying()[ix].pid()<0 && LAMBDAC.modeMatches(ix,3,mode2CC))) {
          const Particle& lam = LAMBDAC.decayProducts()[ix].at(sign*3122)[0];
          const Particle& K0  = LAMBDAC.decayProducts()[ix].at(     310 )[0];
          _h[2]->fill((lam.mom()+K0.mom()).mass());
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h, 1.0, false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[3];
    const map<PdgId,unsigned int> mode1   = { { 3222,1}, { 321,1}, {-321,1} };
    const map<PdgId,unsigned int> mode1CC = { {-3222,1}, { 321,1}, {-321,1} };
    const map<PdgId,unsigned int> mode2   = { { 3122,1}, { 310,1}, { 321,1} };
    const map<PdgId,unsigned int> mode2CC = { {-3122,1}, { 310,1}, {-321,1} };
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BELLE_2002_I566127);

}