1. W JamboreeEric Lançon - ALEPH Week - January 2001 1 Jetset vs Herwig … Once more III Jetset vs Herwig on same selected events

2. W JamboreeEric Lançon - ALEPH Week - January 2001 2 Conclusions from 14-June-2000 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? Herwig Bug

3. W JamboreeEric Lançon - ALEPH Week - January 2001 3 What’s new HERWIG bugs have been fixed by G. Rudolph 1 M Jetset and Herwig same CC03 events have been produced over Christmas by Marcello Today : rapid comparison Jetset vs Herwig With new common Ntuples

4. W JamboreeEric Lançon - ALEPH Week - January 2001 4 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 ? 14-June-2000

5. W JamboreeEric Lançon - ALEPH Week - January 2001 5 Total Event energy 300 Mev more energy in Herwig Still there Notice the small Jetset difference : +0.1 GeV

6. W JamboreeEric Lançon - ALEPH Week - January 2001 6 Charged energy 300 Mev less charged energy in Jetset 14-June-2000

7. W JamboreeEric Lançon - ALEPH Week - January 2001 7 Charged energy 500 Mev less charged energy in Jetset Notice the Jetset difference : +1.48 GeV

8. W JamboreeEric Lançon - ALEPH Week - January 2001 8 Charge multiplicity 0.16 more charged particles in Jetset 14-June-2000

9. W JamboreeEric Lançon - ALEPH Week - January 2001 9 Charge multiplicity 0.1 more charged particles in Herwig Notice the Jetset difference : +2.36

10. W JamboreeEric Lançon - ALEPH Week - January 2001 10 Multiplicity per jet Nb of charged tracks/jetNb of Eflow objects/jet More objects/jet in Jetset 14-June-2000

11. W JamboreeEric Lançon - ALEPH Week - January 2001 11 Multiplicity per jet Nb of charged tracks/jetNb of Eflow objects/jet More objects/jet in HerwigMore objects/jet in Jetset Total Number of objects now

12. W JamboreeEric Lançon - ALEPH Week - January 2001 12  resolution Better  resolution for Herwig  (rec.-gen.) <> = -0.019  0.009 RMS = 6.22 <> = -0.006  0.008 RMS = 5.51 14-June-2000

13. W JamboreeEric Lançon - ALEPH Week - January 2001 13  resolution  (rec.-gen.) <> = -0.033  0.009 RMS = 6.25 <> = -0.022  0.008 RMS = 6.30 Similar  resolution for Herwig ???

14. W JamboreeEric Lançon - ALEPH Week - January 2001 14  (raw-generated) vs  gen. Z  generated Herwig Jetset  (rec.-gen.) vs  gen. Jetset jets are more inside Herwig jets less biased at low  14-June-2000

15. W JamboreeEric Lançon - ALEPH Week - January 2001 15  (raw-generated) vs  gen.  (rec.-gen.) vs  gen. Jetset jets are a still bit less inside

16. W JamboreeEric Lançon - ALEPH Week - January 2001 16 Sum of Pt2 Wider Jetset jets 14-June-2000

17. W JamboreeEric Lançon - ALEPH Week - January 2001 17 Sum of Pt2 a bit Wider HERWIG jets Notice the small Jetset difference : -0.135 GeV

18. W JamboreeEric Lançon - ALEPH Week - January 2001 18 Jet-jet angle Jet 1 Jet 2  Herwig Ws are more ‘opened’  = -0.32  0.04 deg. Strongly related to W mass 14-June-2000

19. W JamboreeEric Lançon - ALEPH Week - January 2001 19 Jet-jet angle Jet 1 Jet 2  This has been cured ! Strongly related to W mass  = 0.01  0.03 deg. Notice the small Jetset difference : +0.42 deg.

20. W JamboreeEric Lançon - ALEPH Week - January 2001 20 Fitted mass : Herwig - Jetset M Herwig - M jetset = 7  7 MeV Before rescaling Super!

21. W JamboreeEric Lançon - ALEPH Week - January 2001 21 Delta fitted mass vs Nb jets in Barrel M Jetset - M Herwig vs number jets in barrel 33 99 2.5 14-June-2000

22. W JamboreeEric Lançon - ALEPH Week - January 2001 22 Delta fitted mass vs Nb jets in Barrel M Jetset - M Herwig vs number jets in barrel

23. W JamboreeEric Lançon - ALEPH Week - January 2001 23 Temporary conclusions Quick look at recently produced Jetset and Herwig MC samples Most of the differences between Jetset and Herwig have been cured At first look : the net result is NO mass shift between the two fragmentation models However : some differences between new and old Jetset produced evts observed –Need to be understood –Effect of common Ntuple reconstruction ? We are on better shape!