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Jetset vs Herwig … Once more

Jetset vs Herwig … Once more. c quark effect Jetset vs Herwig on same selected events. c quark effect. Questions : Is there a difference in efficiency between Jetset and Herwig for the different types of quark flavour in final state ?

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Jetset vs Herwig … Once more

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  1. Jetset vs Herwig… Once more c quark effect Jetset vs Herwig on same selected events Eric Lançon

  2. c quark effect • Questions : • Is there a difference in efficiency between Jetset and Herwig for the different types of quark flavour in final state ? • Are the fitted masses sensitive to quark flavour content of final state? Eric Lançon

  3. Selection efficiency - same 4f evts Jetset 34511 evts Herwig 35011 evts Number of selected evts for mass analysis 1.5 % more selected evts for Herwig Number of c quarks in event Relative difference of efficiency Herwig / Jetset vs number of c quarks in event No real effect Eric Lançon

  4. DMW vs nb c quarks in event All Events Background in reference but not in fitted samples (1093 evt/sample) No quark flavour selection Eric Lançon

  5. DMW vs nb c quarks in event Common events Background in reference but not in fitted samples No quark flavour selection Eric Lançon

  6. No c quark in event Mmin Nchmin 2 (Jetset-Herwig) Eric Lançon

  7. No c quark in event Slimmer Herwig jets Mmin Nchmin Eric Lançon

  8. One c quark in event Mmin Eric Lançon

  9. Two c quarks in event Btag Mmin Eric Lançon

  10. Variation with Nb of c quarks in evt <Mmin> vs nb of c quark in events 2 of distributions Jetset vs Herwig B evt tag and Nch1 vs nb of c quark in events Typical shape The are the only variables with a linear variation Eric Lançon

  11. Conclusions from c quark study • 4q mass selection is 1.5% more efficient on Herwig events, • No real dependence with quark flavour • The are differences between Jetset and Herwig for the c and non-c final states : • those differences tend to compensate (except Btag, Nch1) • The mass shift between Jetset and Herwig is independent of the number of c quarks in final state Eric Lançon

  12. Jetset - Herwig comparison • Same events in same Ntuple • after mass selection (including pairing) • 600K events each before selection • use events which correspond to same jet-jet combination for jetset and herwig • Look at : • global event properties • event/event properties Eric Lançon

  13. Total Event energy 300 Mev more energy in Herwig • Pb of Eflow calibration? • Need Herwig Z0 events This explain the higher efficiency of the selection for Herwig ? Eric Lançon

  14. Charged energy 300 Mev less charged energy in Jetset Eric Lançon

  15. Electromagnetic energy  same electromagnetic energy for Jetset and Herwig Eric Lançon

  16. Charge multiplicity 0.16 more charged particles in Jetset Eric Lançon

  17. Multiplicity per jet Nb of charged tracks/jet Nb of Eflow objects/jet More objects/jet in Jetset Eric Lançon

  18. E jet jetset/Herwig vs  Eric Lançon

  19. Em fraction in jet vs  No  dependence Eric Lançon

  20. Multiplicity in jets vs  Nb of charged tracks/jet Nb of Eflow objects/jet No  dependence Eric Lançon

  21. Fitted mass : Herwig - Jetset MHerwig - Mjetset = 90  8 MeV Before rescaling Eric Lançon

  22. Fitted mass vs Fch and Fem No real dependence / difference Jetset-Herwig Eric Lançon

  23. Fitted mass vs charged multiplicity Some dependence and difference Jetset-Herwig? Eric Lançon

  24.  and  (Jetset-Herwig)  (Jetset-Herwig)  (Jetset-Herwig) Worst  ? … see later Eric Lançon

  25.  (raw-generated) vs  gen. (rec.-gen.) vs gen. Jetset Herwig generated Z • Jetset jets are more inside • Herwig jets less biased at low  Eric Lançon

  26.  resolution (rec.-gen.) Better  resolution for Herwig <> = -0.019  0.009 RMS = 6.22 <> = -0.006  0.008 RMS = 5.51 Eric Lançon

  27.  after fit (fit-rec.) vs gen. (fit-gen.) vs gen. Fit does not correct for the difference in  reconstruction at low angle between Jetset and Herwig Eric Lançon

  28. Delta fitted mass vs Nb jets in Barrel MJetset - MHerwig vs number jets in barrel An effect when NO jet in barrel ? Eric Lançon

  29. Delta fitted mass vs  gen. Min. MJetset - MHerwig vs Min( jet-gen.) Eric Lançon

  30. Sum of Pt2 Wider Jetset jets Eric Lançon

  31. Delta fitted mass vs Sum of Pt2 MJetset - MHerwig vs Sum Pt2 Strong dependence Eric Lançon

  32. Jet-jet angle  = -0.32  0.04 deg. Jet1  Jet2 Strongly related to W mass Herwig Ws are more ‘opened’ Eric Lançon

  33. Delta jet-jet angle vs   (jetset-Herwig) vs number jets in barrel  (jetset-Herwig) vs W gen No real variation Eric Lançon

  34. Conclusions • More reconstructed energy (300 MeV) with Herwig • More charged energy in Herwig (300 MeV) • Calibration of Eflow? Herwig Z0 events needed • Explain difference in efficiency • Larger particle multiplicity in Jetset • Jetset jets are wider • More losses are low/high  • Jetset  resolution worst than Herwig • Jet-Jet angle larger for Herwig than Jetset Which of the two MC data prefer? Eric Lançon

  35. The 18 Variables • Global properties of the event • # charged tracks in an event Nch • charged/total energy Fch • em E fraction in event Fem • Parton-shower related • Minimum jet mass Mmin • Maximum jet mass Mmax • Sum of Pt2 wrt jets SumPT2 • Sum of Angles Ch. Part. wrt Jet 1,2SumAng12 Eric Lançon

  36. The 18 Variables (Contd.) • Hadronisation related • minimum # object in a jet Nobjmin • minimum # of charged track in a jet Nchmin • Max. e.m. energy fraction in 1 deg. cone Max-em-frac • Max. charged track energy fraction Max-ch-trk • # charged particles in leading E jet Nch1 • # charged particles in lowest E jet Nch4 • # objects particles in leading E jet Nobj1 • # objects particles in lowest E jet Nobj4 • Sum Jets Btag SUMPROB • QIPBTAG event prob. PROBE Eric Lançon

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