rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

DELPHI_2001_I526164

Charged and Identified particle spectra in $q\bar{q}$ and $WW$ events
Experiment: DELPHI (LEP)
Inspire ID: 526164
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Eur.Phys.J.C 18 (2000) 203-228, 2000
Beams: e+ e-
Beam energies: (66.5, 66.5); (80.5, 80.5); (86.0, 86.0); (91.5, 91.5); (94.5, 94.5); (100.0, 100.0) GeV
Run details:
  • e+ e- -> q qbar amd W+W- events

Measurement of charged and identified particle production in both $q\bar{q}$ and $W^+W^-$ events at LEP. Need $q\bar{q}$ at all the energies and $W^+W^-$ at 183 and 189 GeV.

Source code: DELPHI_2001_I526164.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/UnstableParticles.hh"
  4#include "Rivet/Projections/FinalState.hh"
  5#include "Rivet/Projections/Thrust.hh"
  6
  7namespace Rivet {
  8
  9
 10  /// @brief DELPHI W decay analysis
 11  class DELPHI_2001_I526164 : public Analysis {
 12  public:
 13
 14    /// Constructor
 15    RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_2001_I526164);
 16
 17
 18    /// @name Analysis methods
 19    ///@{
 20
 21    /// Book histograms and initialise projections before the run
 22    void init() {
 23      // projections
 24      declare(UnstableParticles(),"UFS");
 25      declare(FinalState(),"FS");
 26      // Hisotgram booking
 27      // qqbar
 28      // counters for multiplicities
 29      for(unsigned int ix=0;ix<7;++ix) {
 30        std::ostringstream title;
 31        title << "_n_qq_" << ix;
 32        book(_n_qq[ix],title.str());
 33      }
 34      // spectra
 35      _WW=false;
 36      if(isCompatibleWithSqrtS(183.)) {
 37        book(_h_qq_K0 ,16,1,1);
 38        book(_h_qq_Lam,16,1,3);
 39        book(_h_p_charged[0],7,1,2);
 40        book(_h_p_charged[1],7,1,1);
 41        book(_h_p_chargedB[0],"/TMP/h_7_1_2",refData(8,1,1));
 42        book(_h_p_chargedB[1],"/TMP/h_7_1_1",refData(8,1,1));
 43        book(_h_xi_charged [0],10,1,2);
 44        book(_h_xi_charged [1],10,1,1);
 45        book(_h_xi_chargedB[0],"/TMP/h_10_1_2",refData(10,1,3));
 46        book(_h_xi_chargedB[1],"/TMP/h_10_1_1",refData(10,1,3));
 47        book(_h_pT_charged [0],12,1,2);
 48        book(_h_pT_charged [1],12,1,1);
 49        book(_h_pT_chargedB[0],"/TMP/h_12_1_2",refData(12,1,3));
 50        book(_h_pT_chargedB[1],"/TMP/h_12_1_1",refData(12,1,3));
 51        _WW=true;
 52      }
 53      else if (isCompatibleWithSqrtS(189.)) {
 54        book(_h_qq_K0 ,16,1,2);
 55        book(_h_qq_Lam,16,1,4);
 56        book(_h_p_charged [0],5,1,2);
 57        book(_h_p_charged [1],5,1,1);
 58        book(_h_p_chargedB[0],"/TMP/h_5_1_2",refData(6,1,1));
 59        book(_h_p_chargedB[1],"/TMP/h_5_1_1",refData(6,1,1));
 60        book(_h_xi_charged [0],9,1,2);
 61        book(_h_xi_charged [1],9,1,1);
 62        book(_h_xi_chargedB[0],"/TMP/h_9_1_2",refData(9,1,3));
 63        book(_h_xi_chargedB[1],"/TMP/h_9_1_1",refData(9,1,3));
 64        book(_h_pT_charged [0],11,1,2);
 65        book(_h_pT_charged [1],11,1,1);
 66        book(_h_pT_chargedB[0],"/TMP/h_11_1_2",refData(11,1,3));
 67        book(_h_pT_chargedB[1],"/TMP/h_11_1_1",refData(11,1,3));
 68        for(unsigned int ix=0;ix<3;++ix) {
 69          for(unsigned int iy=0;iy<4;++iy) {
 70            book(_h_xi_ident[ix][iy],13+ix,1,iy+1);
 71          }
 72        }
 73        _WW=true;
 74      }
 75      if(_WW) {
 76        for(unsigned int ix=0;ix<2;++ix) {
 77          for(unsigned int iy=0;iy<5;++iy) {
 78            std::ostringstream title;
 79            title << "_n_WW_" << ix << "_" << iy << "\n";
 80            book(_n_WW[ix][iy],title.str());
 81          }
 82        }
 83      }
 84    }
 85
 86    /// Perform the per-event analysis
 87    void analyze(const Event& event) {
 88      const double mW=80.379*GeV;
 89      struct ParticleOrdering {
 90        bool operator()(const Particle &p1, const Particle & p2) const {
 91          return p1.pid() > p2.pid();
 92        }
 93      };
 94      multimap<Particle,Particles,ParticleOrdering> Wbosons;
 95      // loop over final state particles to find W's
 96      Particles finalState = apply<FinalState>(event,"FS").particles();
 97      // loop over FS particles
 98      for (const Particle & p : finalState) {
 99        Particle parent=p;
100        while(!parent.parents().empty()) {
101          parent=parent.parents()[0];
102          if(parent.abspid()==24 && parent.mass()>20.) break;
103        }
104        if (parent.abspid()!=24) continue;
105        // find those which came from W
106        bool found=false;
107        for (auto & W : Wbosons) {
108          // W already in list add particle to its decay products
109          if (fuzzyEquals(W.first.momentum(),parent.momentum())) {
110            W.second.push_back(p);
111            found=true;
112            break;
113          }
114        }
115        if (!found) {
116          // check W not child
117          bool Wchild=false;
118          for (const Particle & child : parent.children()) {
119            if(child.abspid()==24) {
120              Wchild=true;
121              break;
122            }
123          }
124          // add to list
125          if(!Wchild) {
126            Particles temp = {p};
127            Wbosons.insert(make_pair(parent,temp));
128          }
129        }
130      }
131      // no W's => q qbar event
132      if (Wbosons.empty()) {
133        _n_qq[0]->fill();
134        UnstableParticles ufs=apply<UnstableParticles>(event,"UFS");
135        for (const Particle & p : ufs.particles()) {
136          if(p.abspid()==PID::PIPLUS) {
137            _n_qq[1]->fill();
138            _n_qq[2]->fill();
139          }
140          else if(p.abspid()==PID::KPLUS) {
141            _n_qq[1]->fill();
142            _n_qq[3]->fill();
143          }
144          else if(p.abspid()==PID::PROTON) {
145            _n_qq[1]->fill();
146            _n_qq[5]->fill();
147          }
148          else if(p.abspid()==130 || p.abspid()==310 ) {
149            _n_qq[4]->fill();
150            if(_h_qq_K0) _h_qq_K0->fill(-log(2.*p.p3().mod()/sqrtS()));
151          }
152          else if(p.abspid()==PID::LAMBDA ) {
153            _n_qq[6]->fill();
154            if(_h_qq_Lam) _h_qq_Lam->fill(-log(2.*p.p3().mod()/sqrtS()));
155          }
156        }
157      }
158      else if (Wbosons.size()==2) {
159        bool leptonic[2] = {false,false};
160        unsigned int iboson=0;
161        for(auto& W : Wbosons) {
162          for(const Particle & child : W.first.children()) {
163            // find lepton bosons
164            if(child.abspid()==11 || child.abspid()==13) {
165              leptonic[iboson]=true;
166              break;
167            }
168            // veto events with W-> tau decays
169            else if(child.abspid()==15 )
170              vetoEvent;
171          }
172          ++iboson;
173        }
174        // only fully hadronic or semi-leptonic events
175        if (leptonic[0] && leptonic[1]) vetoEvent;
176        // 0 SL 1 hadronic
177        unsigned int itype= leptonic[0]||leptonic[1] ? 0 : 1;
178        _n_WW[itype][0]->fill();
179        Particles particles;
180        iboson=0;
181        for (auto& W : Wbosons) {
182          if (!leptonic[iboson]) {
183            particles.insert(particles.end(),W.second.begin(),W.second.end());
184          }
185          ++iboson;
186        }
187        // calculate thrust
188        Thrust thrust;
189        thrust.calc(particles);
190        // type of event
191        // loop over particles and fill histos
192        for (const Particle & p : particles) {
193          if (!PID::isCharged(p.pid())) continue;
194          // Get momentum of each particle.
195          const Vector3 mom3 = p.p3();
196          // Scaled momenta.
197          const double mom = mom3.mod();
198          const double xiW = -log(2.*mom/mW);
199          const double xiL = -log(2.*mom/sqrtS());
200          // Get momenta components w.r.t. thrust
201          const double pTinT = dot(mom3, thrust.thrustMajorAxis());
202          const double pToutT = dot(mom3, thrust.thrustMinorAxis());
203          double pT = sqrt(sqr(pTinT)+sqr(pToutT));
204          // fill charged particle hists
205          _h_p_charged  [itype]->fill(mom);
206          _h_xi_charged [itype]->fill(xiL);
207          _h_pT_charged [itype]->fill(pT );
208          _h_p_chargedB [itype]->fill(mom);
209          _h_xi_chargedB[itype]->fill(xiL);
210          _h_pT_chargedB[itype]->fill(pT );
211          // and identified particles
212          if(_h_xi_ident[itype][0]) _h_xi_ident[itype][0]->fill(xiW);
213          _n_WW[itype][1]->fill();
214          if(p.abspid()==PID::PIPLUS) {
215            if(_h_xi_ident[itype][1]) _h_xi_ident[itype][1]->fill(xiW);
216            _n_WW[itype][2]->fill();
217          }
218          else if(p.abspid()==PID::KPLUS) {
219            if(_h_xi_ident[itype][2]) _h_xi_ident[itype][2]->fill(xiW);
220            _n_WW[itype][3]->fill();
221          }
222          else if (p.abspid()==PID::PROTON){
223            if (_h_xi_ident[itype][3]) _h_xi_ident[itype][3]->fill(xiW);
224            _n_WW[itype][4]->fill();
225          }
226        }
227        // boosted specta in W rest frame
228        if (itype==0) {
229        iboson=0;
230        for (auto& W : Wbosons) {
231          ++iboson;
232          if (leptonic[iboson-1]) continue;
233          // boost to rest frame
234          LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(W.first.momentum().betaVec());
235          FourMomentum psum;
236          for (const Particle& p :W.second) psum+=p.momentum();
237            // spectra
238            for (const Particle& p : W.second) {
239              if (!PID::isCharged(p.pid())) continue;
240              // Get momentum of each particle.
241              FourMomentum phad = boost.transform(p.momentum());
242              const Vector3 mom3 = phad.p3();
243              // Scaled momenta.
244              const double mom = mom3.mod();
245              const double scaledMom = 2.*mom/mW;
246              const double xi = -log(scaledMom);
247              // /identified particle spectra
248              if (_h_xi_ident[2][0]) _h_xi_ident[2][0]->fill(xi);
249              if (p.abspid()==PID::PIPLUS) {
250                if(_h_xi_ident[2][1]) _h_xi_ident[2][1]->fill(xi);
251              }
252              else if (p.abspid()==PID::KPLUS) {
253                if (_h_xi_ident[2][2]) _h_xi_ident[2][2]->fill(xi);
254              }
255              else if (p.abspid()==PID::PROTON){
256                if (_h_xi_ident[2][3]) _h_xi_ident[2][3]->fill(xi);
257              }
258            }
259          }
260        }
261      }
262    }
263
264
265    /// Normalise histograms etc., after the run
266    void finalize() {
267      // qq
268      if (_n_qq[0]->effNumEntries()!=0.) {
269        // scale spectra if needed
270        if (_h_qq_K0 )  scale(_h_qq_K0 , 1./ *_n_qq[0]);
271        if (_h_qq_Lam)  scale(_h_qq_Lam, 1./ *_n_qq[0]);
272        for (unsigned int ih=1; ih<7; ++ih) {
273          if (_n_qq[ih]->effNumEntries()==0.) continue;
274          unsigned int ix= ih==1 ? 1 : 2, iy= ih==1 ? 1 : ih-1;
275          // hist for axis
276          BinnedEstimatePtr<int> ratio;
277          book(ratio, ix, 1, iy);
278          for (auto& b : ratio->bins()) {
279            if ( isCompatibleWithSqrtS(b.xEdge()) ) {
280              b = *_n_qq[ih] / *_n_qq[0];
281            }
282          }
283        }
284      }
285      // WW
286      if( _WW && (_n_WW[0][0]->effNumEntries()!=0. || _n_WW[1][0]->effNumEntries()!=0. )) {
287        Estimate0D ratios[2];
288        unsigned int iloc = isCompatibleWithSqrtS(183.) ? 1 : 0;
289        for(unsigned int iw=0;iw<2;++iw) {
290          if(_n_WW[iw][0]->effNumEntries()==0.) continue;
291          // scale distributions
292          scale(_h_p_charged[iw] , 1./ *_n_WW[iw][0]);
293          scale(_h_xi_charged[iw], 1./ *_n_WW[iw][0]);
294          scale(_h_pT_charged[iw], 1./ *_n_WW[iw][0]);
295          scale(_h_p_chargedB[iw] , 1./ *_n_WW[iw][0]);
296          scale(_h_xi_chargedB[iw], 1./ *_n_WW[iw][0]);
297          scale(_h_pT_chargedB[iw], 1./ *_n_WW[iw][0]);
298          for(unsigned int iy=0;iy<4;++iy) {
299            if(_h_xi_ident[iw][iy]) {
300              scale(_h_xi_ident[iw][iy], 1./ *_n_WW[iw][0]);
301              if(iw==0)
302                scale(_h_xi_ident[2][iy], 1./ *_n_WW[iw][0]);
303            }
304          }
305          // charge mult
306          ratios[iw] =  *_n_WW[iw][1]/ *_n_WW[iw][0];
307          // sort out identified particle multiplicities
308          if(iloc==0) {
309            for(unsigned int iy=2;iy<5;++iy) {
310              Estimate0D R = *_n_WW[iw][iy]/ *_n_WW[iw][0];
311              BinnedEstimatePtr<int> mult;
312              book(mult, 4, 1,  2*(iy-1)-iw);
313              for (auto& b : mult->bins())
314                b.set(R.val(), R.errPos());
315            }
316          }
317        }
318        // charged mults
319        for(unsigned int ii=0;ii<2;++ii) {
320          BinnedEstimatePtr<int> mult;
321          book(mult,3,1,1 + 2*ii);
322          mult->bin(2-iloc).set(ratios[1-ii].val(), ratios[1-ii].errPos());
323        }
324        // difference histos
325        // momentum
326        YODA::Estimate1D htemp = _h_p_chargedB[0]->mkEstimate();
327        htemp.scale(2.);
328        Estimate1DPtr hnew;
329        book(hnew,6+2*iloc,1,1);
330        *hnew = *_h_p_chargedB[1] - htemp;
331        hnew->setPath("/"+name()+"/"+mkAxisCode(6+2*iloc,1,1));
332        // xi
333        YODA::Estimate1D htemp2 = _h_xi_chargedB[0]->mkEstimate();
334        htemp2.scale(2.);
335        Estimate1DPtr hnew2;
336        book(hnew2,9+iloc,1,3);
337        *hnew2 = *_h_xi_chargedB[1] - htemp2;
338        hnew2->setPath("/"+name()+"/"+mkAxisCode(9+iloc,1,3));
339        // pt
340        YODA::Estimate1D hytemp3 = _h_pT_chargedB[0]->mkEstimate();
341        hytemp3.scale(2.);
342        Estimate1DPtr hnew3;
343        book(hnew3,11+iloc,1,3);
344        *hnew3 = *_h_pT_chargedB[1] - hytemp3;
345        hnew3->setPath("/"+name()+"/"+mkAxisCode(11+iloc,1,3));
346      }
347    }
348
349    ///@}
350
351
352    /// @name Histograms
353    ///@{
354    // qqbar
355    Histo1DPtr _h_qq_K0,_h_qq_Lam;
356    CounterPtr _n_qq[7];
357    // WW
358    Histo1DPtr _h_p_charged [2],_h_xi_charged [2],_h_pT_charged [2],_h_xi_ident[3][4];
359    Histo1DPtr _h_p_chargedB[2],_h_xi_chargedB[2],_h_pT_chargedB[2];
360    CounterPtr _n_WW[2][5];
361    bool _WW;
362    ///@}
363
364
365  };
366
367
368  RIVET_DECLARE_PLUGIN(DELPHI_2001_I526164);
369
370}