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Rivet analyses reference

DELPHI_2003_I620250

Measurements of event shapes by DELPHI, above and below $m_Z$
Experiment: DELPHI (LEP)
Inspire ID: 620250
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Eur.Phys.J. C29 (2003) 285-312
Beams: e+ e-
Beam energies: (22.5, 22.5); (33.0, 33.0); (38.0, 38.0); (91.5, 91.5); (94.5, 94.5); (96.0, 96.0); (98.0, 98.0); (100.0, 100.0); (101.0, 101.0); (102.5, 102.5); (103.5, 103.5) GeV
Run details:
  • Hadronic Z decay events generated below the Z pole

Measurement of a wide range of event shapes by DELPHI at energies below the Z pole using radiative events and above $m_Z$ from LEP2. This analyses allows the energy dependence of simulations to be studied. Only the distributions and not the means are implemented.

Source code: DELPHI_2003_I620250.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/Thrust.hh"
#include "Rivet/Projections/Sphericity.hh"
#include "Rivet/Projections/Hemispheres.hh"
#include "Rivet/Projections/ParisiTensor.hh"

namespace Rivet {


  /// @brief DELPHI event shapes below the Z pole
  class DELPHI_2003_I620250 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(DELPHI_2003_I620250);


    /// @name Analysis methods
    //@{

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

      // Initialise and register projections
      declare(Beam(), "Beams");
      const FinalState fs;
      declare(fs, "FS");
      const Thrust thrust(fs);
      declare(thrust, "Thrust");
      declare(Sphericity(fs), "Sphericity");
      declare(ParisiTensor(fs), "Parisi");
      declare(Hemispheres(thrust), "Hemispheres");

      // find the beam energy
      unsigned int offset = 0;
      int offset2 = -1;
      if      (fuzzyEquals(sqrtS()/GeV, 45, 1E-3)) offset = 1;
      else if (fuzzyEquals(sqrtS()/GeV, 66, 1E-3)) offset = 2;
      else if (fuzzyEquals(sqrtS()/GeV, 76, 1E-3)) offset = 3;
      else if (fuzzyEquals(sqrtS()/GeV, 183  , 1E-3)) {
	offset2= 0;			   
	offset = 1;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 189  , 1E-3)) {
	offset2= 0;			   
	offset = 2;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 192  , 1E-3)) {
	offset2= 0;			   
	offset = 3;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 196  , 1E-3)) {
	offset2= 0;			   
	offset = 4;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 200  , 1E-3)) {
	offset2= 1;			   
	offset = 1;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 202  , 1E-3)) {
	offset2= 1;			   
	offset = 2;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 205  , 1E-3)) {
	offset2= 1;			   
	offset = 3;			   
      }					   
      else if (fuzzyEquals(sqrtS()/GeV, 207  , 1E-3)) {
	offset2= 1;
	offset = 4;
      }
      else    MSG_ERROR("Beam energy not supported!");
      // Book the histograms
      if(offset2<0) {
	book(_h_thrust,  1, 1, offset);
	book(_h_major ,  2, 1, offset);
	book(_h_minor ,  3, 1, offset);
	book(_h_sphericity,  4, 1, offset);
	book(_h_planarity,  5, 1, offset);
	book(_h_oblateness,  6, 1, offset);
	book(_h_heavy_jet_mass,  7, 1, offset);
	book(_h_light_jet_mass,  9, 1, offset);
	book(_h_diff_jet_mass, 10, 1, offset);
	book(_h_total_jet_mass, 11, 1, offset);
	book(_h_heavy_jet_mass_E,  8, 1, offset);
	book(_h_total_jet_mass_E, 12, 1, offset);
	book(_h_wide_broading, 13, 1, offset);
	book(_h_narrow_broading, 14, 1, offset);
	book(_h_total_broading, 15, 1, offset);
	book(_h_diff_broading, 16, 1, offset);
	book(_h_CParam, 17, 1, offset);
      }
      else {
	book(_h_rap             , 30+offset2, 1, offset);
	book(_h_xi              , 32+offset2, 1, offset);
	book(_h_pTIn            , 34+offset2, 1, offset);
	book(_h_pTOut           , 36+offset2, 1, offset);
	book(_h_thrust          , 38+offset2, 1, offset);
	book(_h_major           , 40+offset2, 1, offset);
	book(_h_minor           , 42+offset2, 1, offset);
	book(_h_oblateness      , 44+offset2, 1, offset);
	book(_h_wide_broading   , 46+offset2, 1, offset);
	book(_h_total_broading  , 48+offset2, 1, offset);
	book(_h_diff_broading   , 50+offset2, 1, offset);
	book(_h_CParam          , 52+offset2, 1, offset);
	book(_h_DParam          , 54+offset2, 1, offset);
	book(_h_heavy_jet_mass  , 56+offset2, 1, offset);
	book(_h_heavy_jet_mass_P, 58+offset2, 1, offset);
	book(_h_heavy_jet_mass_E, 60+offset2, 1, offset);
	book(_h_light_jet_mass  , 62+offset2, 1, offset);
	book(_h_diff_jet_mass   , 64+offset2, 1, offset);
	book(_h_sphericity      , 66+offset2, 1, offset);
	book(_h_planarity       , 68+offset2, 1, offset);
	book(_h_aplanarity      , 70+offset2, 1, offset);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {

      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double meanBeamMom = ( beams.first.p3().mod() +
                                   beams.second.p3().mod() ) / 2.0;
      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);

      const Thrust& thrust = apply<Thrust>(event, "Thrust");
      // thrust related observables
      _h_thrust    ->fill(1.-thrust.thrust()  );
      _h_major     ->fill(thrust.thrustMajor());
      _h_minor     ->fill(thrust.thrustMinor());
      _h_oblateness->fill(thrust.oblateness() );

      // sphericity related
      const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
      _h_sphericity->fill(sphericity.sphericity());
      _h_planarity ->fill(sphericity.planarity() );
      if(_h_aplanarity) _h_aplanarity->fill(sphericity.aplanarity());
      // hemisphere related
      const Hemispheres& hemi = apply<Hemispheres>(event, "Hemispheres");
      // standard jet masses
      _h_heavy_jet_mass->fill(hemi.scaledM2high());
      _h_light_jet_mass->fill(hemi.scaledM2low() );
      _h_diff_jet_mass ->fill(hemi.scaledM2diff());
      if(_h_total_jet_mass) _h_total_jet_mass->fill(hemi.scaledM2low()+hemi.scaledM2high());
      // jet broadening
      _h_wide_broading  ->fill(hemi.Bmax() );
      if(_h_narrow_broading) _h_narrow_broading->fill(hemi.Bmin() );
      _h_total_broading ->fill(hemi.Bsum() );
      _h_diff_broading  ->fill(hemi.Bdiff());
      // E and p scheme jet masses
      Vector3 axis = thrust.thrustAxis();
      FourMomentum p4WithE, p4AgainstE;
      FourMomentum p4WithP, p4AgainstP;
      double Evis(0);
      for (const Particle& p : apply<FinalState>(event, "FS").particles()) {
	Vector3 p3 = p.momentum().vector3().unitVec();
	const double   E = p.momentum().E();
	Evis += E;
	p3 = E*p3;
	const double p3Para = dot(p3, axis);
	FourMomentum p4E(E,p3.x(),p3.y(),p3.z());
	FourMomentum p4P(p.p3().mod(),p.p3().x(),p.p3().y(),p.p3().z());
	if (p3Para > 0)      {
	  p4WithE    += p4E;
	  p4WithP    += p4P;
	}
	else if (p3Para < 0) {
	  p4AgainstE += p4E;
	  p4AgainstP += p4P;
	}
	else {
	  MSG_WARNING("Particle split between hemispheres");
	  p4WithE    += 0.5 * p4E;
	  p4AgainstE += 0.5 * p4E;
	  p4WithP    += 0.5 * p4P;
	  p4AgainstP += 0.5 * p4P;
	}
      }
      // E scheme
      const double mass2With_E    = p4WithE.mass2()/sqr(Evis);
      const double mass2Against_E = p4AgainstE.mass2()/sqr(Evis);
      // fill the histograms
      _h_heavy_jet_mass_E->fill(max(mass2With_E,mass2Against_E));
      if(_h_total_jet_mass_E) _h_total_jet_mass_E->fill(mass2With_E+mass2Against_E);
      // pscheme
      const double mass2With_P    = p4WithP.mass2()/sqr(Evis);
      const double mass2Against_P = p4AgainstP.mass2()/sqr(Evis);
      // fill the histograms
      if(_h_heavy_jet_mass_P) _h_heavy_jet_mass_P->fill(max(mass2With_P,mass2Against_P));
      
      MSG_DEBUG("Calculating Parisi params");
      const ParisiTensor& parisi = apply<ParisiTensor>(event, "Parisi");
      _h_CParam->fill(parisi.C());
      if(_h_DParam) _h_DParam->fill(parisi.D());

      // single particle distributions
      const FinalState& fs = apply<FinalState>(event, "FS");
      if(_h_xi) {
	for (const Particle& p : fs.particles()) {
	  if( ! PID::isCharged(p.pid())) continue;
	  // Get momentum and energy of each particle.
	  const Vector3 mom3 = p.p3();
	  const double energy = p.E();
	  
	  // Scaled momenta.
	  const double mom = mom3.mod();
	  const double scaledMom = mom/meanBeamMom;
	  const double logInvScaledMom = -std::log(scaledMom);
	  _h_xi->fill(logInvScaledMom);
	  
	  // Get momenta components w.r.t. thrust and sphericity.
	  const double momT = dot(thrust.thrustAxis(), mom3);
	  const double pTinT = dot(mom3, thrust.thrustMajorAxis());
	  const double pToutT = dot(mom3, thrust.thrustMinorAxis());
	  _h_pTIn ->fill(fabs(pTinT/GeV));
	  _h_pTOut->fill(fabs(pToutT/GeV));
	  
	  // Calculate rapidities w.r.t. thrust and sphericity.
	  const double rapidityT = 0.5 * std::log((energy + momT) / (energy - momT));
	  _h_rap->fill(fabs(rapidityT));
	  MSG_TRACE(fabs(rapidityT) << " " << scaledMom/GeV);
	}
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {

      normalize(_h_thrust          );
      normalize(_h_major           );
      normalize(_h_minor           );
      normalize(_h_sphericity      );
      normalize(_h_planarity       );
      if(_h_aplanarity) normalize(_h_aplanarity       );
      normalize(_h_oblateness      );
      normalize(_h_heavy_jet_mass  );
      normalize(_h_light_jet_mass  );
      normalize(_h_diff_jet_mass   );
      if(_h_total_jet_mass) normalize(_h_total_jet_mass  );
      normalize(_h_heavy_jet_mass_E);
      if(_h_total_jet_mass_E) normalize(_h_total_jet_mass_E);
      if(_h_heavy_jet_mass_P) normalize(_h_heavy_jet_mass_P);
      normalize(_h_wide_broading   );
      if(_h_narrow_broading) normalize(_h_narrow_broading );
      normalize(_h_total_broading  );
      normalize(_h_diff_broading   );
      normalize(_h_CParam   );
      if(_h_DParam) normalize(_h_DParam   );
      if(_h_xi) {
	scale(_h_xi   ,1./sumOfWeights());
	scale(_h_pTIn ,1./sumOfWeights());
	scale(_h_pTOut,1./sumOfWeights());
	scale(_h_rap  ,1./sumOfWeights());
      }
    }

    //@}


    /// @name Histograms
    //@{
    Histo1DPtr _h_thrust,_h_major,_h_minor;
    Histo1DPtr _h_sphericity,_h_planarity,_h_aplanarity,_h_oblateness;
    Histo1DPtr _h_heavy_jet_mass,_h_light_jet_mass,_h_diff_jet_mass,_h_total_jet_mass;
    Histo1DPtr _h_heavy_jet_mass_E,_h_total_jet_mass_E;
    Histo1DPtr _h_heavy_jet_mass_P;
    Histo1DPtr _h_wide_broading,_h_narrow_broading,_h_total_broading,_h_diff_broading;
    Histo1DPtr _h_CParam,_h_DParam;
    Histo1DPtr _h_xi, _h_pTIn, _h_pTOut,_h_rap;
    //@}
  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(DELPHI_2003_I620250);


}