Rivet Analyses Reference

ZEUS_1995_I392386

Charged particle multiplicity and momentum spectra in Breit frame at ZEUS
Experiment: ZEUS (HERA)
Inspire ID: 392386
Status: VALIDATED
Authors:
  • Suzie Kim
  • Hannes Jung
References:
  • Z.Phys.C67:93-108,1995
  • DOI:10.1007/BF01564824
  • arXiv: hep-ex/9501012
  • DESY 95-007
Beams: e- p+, p+ e-
Beam energies: (26.7, 820.0); (820.0, 26.7) GeV
    No run details listed

Charged particle multiplicity and momentum spectra in Deep Inelastic Scattering event are measured at ZEUS. The analysis is performed in Breit frame. The analysis covers the kinematic range of $10 < Q^2 < 1280$ GeV$^2$ and $6 \times 10^{-4} < x_{bj} < 5 \times 10^{-2}$.

Source code: ZEUS_1995_I392386.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/DISKinematics.hh"


namespace Rivet {

const vector<double> QEdges {10., 20., 40., 80., 160., 320.};
const vector<double> xEdges {0.6e-3,1.2e-3,2.4e-3,1.0e-2,5.0e-2};

  /// @brief Charged particle multiplicity and momentum spectra in Breit frame at ZEUS
  class ZEUS_1995_I392386 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ZEUS_1995_I392386);


    /// @name Analysis methods
    ///@{
      
    /// Book histograms and initialise projections before the run
    void init() {
        
      // Initialise and register projections
        declare(DISKinematics(), "Kinematics");
        
      // The basic final-state projection:
      // all final-state particles within
      // the given eta acceptance
        const ChargedFinalState fs;
        declare(fs, "FS");


      // Book histograms
      // specify custom binning
      // take binning from reference data using HEPData ID (digits in "d01-x01-y01" etc.)
      
        for(int iQ = 0; iQ < 11; ++iQ) {
          book(_Nevt_after_cuts_Q[iQ], "TMP/Nevt_after_cuts_Q"+ to_string(iQ));     
        }

        
        book(_h["mult1"],"TMP/mult 1", refData(1, 1, 1)); // Multiplicity
        book(_h["mult1_Q"],"TMP/mult 1_1", refData(1, 1, 1));
        book(_h["mult2"],"TMP/mult 2", refData(2, 1, 1));
        book(_h["mult2_Q"],"TMP/mult 2_1", refData(2, 1, 1));
        book(_h["mult3"], "TMP/mult 3", refData(3, 1, 1));
        book(_h["mult3_Q"], "TMP/mult 3_1",refData(3, 1, 1));
        book(_h["mult4"], "TMP/mult 4", refData(4, 1, 1));
        book(_h["mult4_Q"],"TMP/mult 4_1", refData(4, 1, 1));
        
        book(_h["mom1"], "TMP/mult 5", refData(5, 1, 1)); // Momentum spectra
        book(_h["mom1_Q"],"TMP/mult 5_1", refData(5, 1, 1));
        book(_h["mom2"], "TMP/mult 6", refData(6, 1, 1));
        book(_h["mom2_Q"],"TMP/mult 6_1", refData(6, 1, 1));
        book(_h["mom3"], "TMP/mult 7", refData(7, 1, 1));
        book(_h["mom3_Q"],"TMP/mult 7_1", refData(7, 1, 1));
        book(_h["mom4"], "TMP/mult 8", refData(8, 1, 1));
        book(_h["mom4_Q"], "TMP/mult 8_1", refData(8, 1, 1));
        
        book(_h_mult1, 1,1,1);
        book(_h_mult2, 2,1,1);
        book(_h_mult3, 3,1,1);
        book(_h_mult4, 4,1,1);
        book(_h_mom1, 5,1,1);
        book(_h_mom2, 6,1,1);
        book(_h_mom3, 7,1,1);
        book(_h_mom4, 8,1,1);
        
        book(_h["nch1"], 9, 1, 1);  // Multiplicity
        book(_h["nch2"], 10, 1, 1);
        book(_h["nch3"], 10, 1, 2);
        book(_h["nch4"], 10, 1, 3);
        book(_h["nch5"], 11, 1, 1);
        book(_h["nch6"], 11, 1, 2);
        book(_h["nch7"], 11, 1, 3);
        book(_h["nch8"], 11, 1, 4);
        book(_h["nch9"], 12, 1, 1);
        book(_h["nch10"], 12, 1, 2);
        
        book(_h["loginvmom1"], 13, 1, 1); // Momentum spectra
        book(_h["loginvmom2"], 14, 1, 1);
        book(_h["loginvmom3"], 14, 1, 2);
        book(_h["loginvmom4"], 14, 1, 3);
        book(_h["loginvmom5"], 15, 1, 1);
        book(_h["loginvmom6"], 15, 1, 2);
        book(_h["loginvmom7"], 15, 1, 3);
        book(_h["loginvmom8"], 15, 1, 4);
        book(_h["loginvmom9"], 16, 1, 1);
        book(_h["loginvmom10"], 16, 1, 2);
        
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
        const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "FS");
        const DISKinematics& dk = applyProjection<DISKinematics>(event, "Kinematics");

        double xbj = dk.x(); // momentum fraction
        double Q2 = dk.Q2()/GeV; // momentum transfer
        const LorentzTransform Breitboost = dk.boostBreit();
        
        // Multiplicity counters
        int n911(0), n1011(0), n1012(0), n1013(0), n1111(0), n1112(0), n1113(0), n1114(0), n1211(0), n1212(0);


        if(0.6e-3<xbj && xbj<1.2e-3) {
            if(10<Q2 && Q2<20) {
                    _Nevt_after_cuts_Q[1] -> fill();
            }
            if(10<Q2 && Q2<20) {
                  _Nevt_after_cuts_Q[2] -> fill();
            }
            if(20<Q2 && Q2<40) {
                  _Nevt_after_cuts_Q[3] -> fill();
            }
            if(40<Q2 && Q2<80) {
                  _Nevt_after_cuts_Q[4] -> fill();
            }
        }
        if(2.4e-3<xbj && xbj<1.0e-2) {
            if(20<Q2 && Q2<40) {
                  _Nevt_after_cuts_Q[5] -> fill();
            }
            if(40<Q2 && Q2<80){
                  _Nevt_after_cuts_Q[6] -> fill();
            }
            if(80<Q2 && Q2<160) {
                  _Nevt_after_cuts_Q[7] -> fill();
            }
            if(160<Q2 && Q2<320) {
                 _Nevt_after_cuts_Q[8] -> fill();
            }
        }
        if(1.0e-2<xbj && xbj<5.0e-2) {
            if(320<Q2 && Q2<640) {
                 _Nevt_after_cuts_Q[9] -> fill();
            }
            if(640<Q2 && Q2<1280) {
                 _Nevt_after_cuts_Q[10] -> fill();
            }
        }
            

        for (const Particle& p : cfs.particles()) {
            //??? calculating ln(1/x_p) ??? --> part to ask
            const FourMomentum BrMom = Breitboost.transform(p.momentum());
            double pp = sqrt(BrMom.px()*BrMom.px() + BrMom.py()*BrMom.py() + BrMom.pz()*BrMom.pz() );
            double xp = 2*pp/(sqrt(Q2));
            const double logInvScaledMom = log(1/xp);
            
            if ( BrMom.pz() > 0. ) continue;
            
            if(0.6e-3<xbj && xbj<1.2e-3) {
                _h["mom1"] ->fill(Q2, logInvScaledMom);
                _h["mom1_Q"] ->fill(Q2);
                if(10<Q2 && Q2<20) {
                    _h["loginvmom1"] ->fill(logInvScaledMom);
                    ++n911;
                }
            }
            
          if(1.2e-3<xbj && xbj<2.4e-3) {
                _h["mom2"] ->fill(Q2, logInvScaledMom);
                _h["mom2_Q"] ->fill(Q2);
              if(10<Q2 && Q2<20) {
                  _h["loginvmom2"] ->fill(logInvScaledMom);
                  ++n1011;
                  }
              if(20<Q2 && Q2<40) {
                  _h["loginvmom3"] ->fill(logInvScaledMom);
                  ++n1012;
                  }
              if(40<Q2 && Q2<80) {
                  _h["loginvmom4"] ->fill(logInvScaledMom);
                  ++n1013;
                  }
            }
            
            if(2.4e-3<xbj && xbj<1.0e-2) {
                _h["mom3"] ->fill(Q2, logInvScaledMom);
                _h["mom3_Q"] ->fill(Q2);
                if(20<Q2 && Q2<40) {
                    _h["loginvmom5"] ->fill(logInvScaledMom);
                    ++n1111;
                    }
                if(40<Q2 && Q2<80){
                    _h["loginvmom6"] ->fill(logInvScaledMom);
                    ++n1112;
                    }
                if(80<Q2 && Q2<160) {
                    _h["loginvmom7"] ->fill(logInvScaledMom);
                    ++n1113;
                    }
                if(160<Q2 && Q2<320) {
                    _h["loginvmom8"] ->fill(logInvScaledMom);
                    ++n1114;
                    }
            }
            
            if(1.0e-2<xbj && xbj<5.0e-2) {
                _h["mom4"] ->fill(Q2,logInvScaledMom);
                _h["mom4_Q"] ->fill(Q2);
                if(320<Q2 && Q2<640) {
                    _h["loginvmom9"] ->fill(logInvScaledMom);
                    ++n1211;
                    }
                    if(640<Q2 && Q2<1280) {
                    _h["loginvmom10"] ->fill(logInvScaledMom);
                    ++n1212;
                    }
            }
            
            }
        
        if(0.6e-3<xbj && xbj<1.2e-3) {
            if(10<Q2 && Q2<20) {
                _h["mult1"] ->fill(Q2, n911);
                _h["mult1_Q"] ->fill(Q2);
                _h["nch1"] ->fill(n911);
            }
        }
        
      if(1.2e-3<xbj && xbj<2.4e-3) {
          if(10<Q2 && Q2<80) {
            _h["mult2"] ->fill(Q2, n1011+n1012+n1013);
            _h["mult2_Q"] ->fill(Q2);
              if(10<Q2 && Q2<20) {
                  _h["nch2"] ->fill(n1011); }
              if(20<Q2 && Q2<40) {
                  _h["nch3"] ->fill(n1012);}
              if(40<Q2 && Q2<80) {
                  _h["nch4"] ->fill(n1013);}
          }
        }
        
        if(2.4e-3<xbj && xbj<1.0e-2) {
            _h["mult3"] ->fill(Q2,n1111+n1112+n1113+n1114);
            _h["mult3_Q"] ->fill(Q2);
            if(20<Q2 && Q2<40) {
                _h["nch5"] ->fill(n1111);}
            if(40<Q2 && Q2<80) {
                _h["nch6"] ->fill(n1112);}
            if(80<Q2 && Q2<160) {
                _h["nch7"] ->fill(n1113);}
            if(160<Q2 && Q2<320) {
                _h["nch8"] ->fill(n1114);}

        }
        
        if(1.0e-2<xbj && xbj<5.0e-2) {
            _h["mult4"] ->fill(Q2, n1211+n1212);
            _h["mult4_Q"] ->fill(Q2);
            if(320<Q2 && Q2<640) {
                _h["nch9"] ->fill(n1211);}
            if(640<Q2 && Q2<1280) {
                _h["nch10"] ->fill(n1212); }
        }
        
    }

      
    /// Normalise histograms etc., after the run
    void finalize() {
   //   normalize(_h["XXXX"]); // normalize to unity
        divide(_h["mult1"],_h["mult1_Q"],_h_mult1); // Q versus Multiplicity
        divide(_h["mult2"],_h["mult2_Q"],_h_mult2);
        divide(_h["mult3"],_h["mult3_Q"],_h_mult3);
        divide(_h["mult4"],_h["mult4_Q"],_h_mult4);
        divide(_h["mom1"],_h["mom1_Q"],_h_mom1); // Q versus Momentum
        divide(_h["mom2"],_h["mom2_Q"],_h_mom2);
        divide(_h["mom3"],_h["mom3_Q"],_h_mom3);
        divide(_h["mom4"],_h["mom4_Q"],_h_mom4);
        
        
        normalize(_h["nch1"]); //multiplicity
        normalize(_h["nch2"]);
        normalize(_h["nch3"]);
        normalize(_h["nch4"]);
        normalize(_h["nch5"]);
        normalize(_h["nch6"]);
        normalize(_h["nch7"]);
        normalize(_h["nch8"]);
        normalize(_h["nch9"]);
        normalize(_h["nch10"]);

        if(dbl(*_Nevt_after_cuts_Q[1])>0 ) scale(_h["loginvmom1"],1./ *_Nevt_after_cuts_Q[1]);  //momentum
        if(dbl(*_Nevt_after_cuts_Q[2])>0 ) scale(_h["loginvmom2"],1./ *_Nevt_after_cuts_Q[2]);
        if(dbl(*_Nevt_after_cuts_Q[3])>0 ) scale(_h["loginvmom3"],1./ *_Nevt_after_cuts_Q[3] );
        if(dbl(*_Nevt_after_cuts_Q[4])>0 ) scale(_h["loginvmom4"],1./ *_Nevt_after_cuts_Q[4] );
        if(dbl(*_Nevt_after_cuts_Q[5])>0 ) scale(_h["loginvmom5"],1./ *_Nevt_after_cuts_Q[5] );
        if(dbl(*_Nevt_after_cuts_Q[6])>0 ) scale(_h["loginvmom6"],1./ *_Nevt_after_cuts_Q[6]);
        if(dbl(*_Nevt_after_cuts_Q[7])>0 ) scale(_h["loginvmom7"],1./ *_Nevt_after_cuts_Q[7]);
        if(dbl(*_Nevt_after_cuts_Q[8])>0 ) scale(_h["loginvmom8"],1./ *_Nevt_after_cuts_Q[8]);
        if(dbl(*_Nevt_after_cuts_Q[9])>0 ) scale(_h["loginvmom9"],1./ *_Nevt_after_cuts_Q[9] );
        if(dbl(*_Nevt_after_cuts_Q[10])>0 ) scale(_h["loginvmom10"],1./ *_Nevt_after_cuts_Q[10] );


        
     // scale(_h["ZZZZ"], crossSection()/picobarn/sumW()); // norm to generated cross-section in pb (after cuts)

    }

    ///@}
      

    /// @name Histograms
    ///@{
      
      Scatter2DPtr _h_mult1;
      Scatter2DPtr _h_mult2;
      Scatter2DPtr _h_mult3;
      Scatter2DPtr _h_mult4;
      Scatter2DPtr _h_mom1;
      Scatter2DPtr _h_mom2;
      Scatter2DPtr _h_mom3;
      Scatter2DPtr _h_mom4;
      
    map<string, Histo1DPtr> _h;
    map<string, Profile1DPtr> _p;
    map<string, CounterPtr> _c;
    CounterPtr _Nevt_after_cuts_Q[11];
    BinnedHistogram _h_invmom1,_h_invmom2,_h_invmom3;

    ///@}


  };


  RIVET_DECLARE_PLUGIN(ZEUS_1995_I392386);

}