Rivet analyses

Charged-particle multiplicity in Υ(4S) decays

Experiment: CLEOII (CESR)

Inspire ID: 504672

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D61 (2000) 072002

Beams: * *

Beam energies: ANY

Run details: - Upsilon(4S) decays

Charged particle multiplicity in Υ(4S) decays measured by CLEOII.

Source code:CLEOII_1999_I504672.cc

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

namespace Rivet {


  /// @brief Charged particle multplicity in Upsilon 4s decays
  class CLEOII_1999_I504672 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1999_I504672);


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

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(UnstableParticles(), "UFS");

      // Book histograms
      book(_n_tot  , 1, 1, 1);
      book(_n_lep  , 1, 1, 2);
      book(_n_nolep, 1, 1, 3);
      book(_h_n    , 2, 1, 1);
      book(_n_Ups_All  ,"/TMP/n_Ups_All");
      book(_n_Ups_Lep  ,"/TMP/n_Ups_Lep");
      book(_n_Ups_NoLep,"/TMP/n_Ups_NoLep");
    }

    void findChildren(const Particle & p,int & nCharged, int & nLep) {
      bool isBottom = PID::isBottomHadron(p.pid());
      for (const Particle& child : p.children()) {
        if (child.children().empty()) {
          if (PID::isCharged(child.pid()))  ++nCharged;
          if (isBottom && (child.abspid()==11||child.abspid()==13))  ++nLep;
        }
        else {
          findChildren(child,nCharged,nLep);
        }
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      for (const Particle& p :  apply<FinalState>(event, "UFS").particles(Cuts::pid==300553)) {
        _n_Ups_All->fill();
        int nCharged(0),nLep(0);
        findChildren(p,nCharged,nLep);
        _h_n->fill(nCharged);
        _n_tot->fill(Ecm, nCharged);
        if(nLep==2) {
          _n_lep  ->fill(Ecm, nCharged);
          _n_Ups_Lep->fill();
        }
        else {
          _n_nolep->fill(Ecm, nCharged);
          _n_Ups_NoLep->fill();
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_n    , 1./ *_n_Ups_All  );
      scale(_n_tot  , 1./ *_n_Ups_All  );
      scale(_n_lep  , 1./ *_n_Ups_Lep  );
      scale(_n_nolep, 1./ *_n_Ups_NoLep);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_n;
    BinnedHistoPtr<string> _n_tot,_n_lep,_n_nolep;
    CounterPtr _n_Ups_All,_n_Ups_Lep,_n_Ups_NoLep;
    const string Ecm = "10.6";

    /// @}


  };


  RIVET_DECLARE_PLUGIN(CLEOII_1999_I504672);

}