1. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone A j u m p i n t o t h e F u t u r e !

2. VLHC the Very Large Hadron Collider

3. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Concept: 2 stages project ? Concept: 2 stages project ? Stage 1: Build a BIG TUNNEL, fill with a “cheap” 40 TeV machine; ? Stage 2: Later upgrade it to 200 TeV; ? Place: Fermilab (?) ? Take advantage of the space and excellent geology around Fermilab; ? Use the avaiable facilities; ? When: 2020 (?) ? TESLA (2013) Cost (ECB): ~ 4130 M$ ? Cost (ECB): ~ 4130 M$ (3790 M$ for SSC Y2001$) (3790 M$ for SSC Y2001$) 2004 2009 2013 VLHC TESLA/LC 2020 US Expenses

4. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone 200

5. Fermilab MichiganLake Tevatron

6. why Fermilab ?

7. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone

9. MB studies for Detector & Trigger use - Comparison of Pythia and Isajet (E4-WG3 Detectors) U- UU- Understand the particle/Energy flux, Multiplicity, PT, <PT>… - W- W- W- Which Rapidity Region we have to cover ? - H- H- H- How well MC Generators do ? (what is your opinion?) - …- …- …- … only then start to think about a VHM Trigger

10. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Total Cross Section Physical Process  s=40 TeV  s=100 TeV  s=175 TeV  s=200 TeV Elastic Cross Section ---- Single Diffractive 7.60 mb 7.60 mb 7.96 mb 7.96 mb 8.17 mb 8.17 mb 8.22 mb 8.22 mb Double Diffractive 11.38 mb 11.38 mb 12.83 mb 12.83 mb 13.73 mb 13.73 mb 13.95 mb 13.95 mb Low P T Processes ---- Inelastic Cross Section 93.07 mb 93.07 mb 107.1 mb 107.1 mb 116.7 mb 116.7 mb 119.2 mb 119.2 mb Total Cross Section---- PYTHIA 6.129

11. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Total Cross Section Physical Process  s=40 TeV  s=100 TeV  s=175 TeV  s=200 TeV Elastic Cross Section ---- Single Diffractive---- Low P T Processes---- Inelastic Cross Section 137 mb 157 mb- 174 mb Total Cross Section---- ISAJET 7.51 “No hard scattering at all; events consist only of beam jets. To represent the total cross section it’s better to use a sample of TWOJET events with lower limit on PT chosen to give a cross section equal to the inelastic cross section or to use a mixture of MINIMUM BIAS and TWOJET events” - ISAJET Manual

12. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone hep-ph 0011157

13. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone ? Generated 20000 Minimum Bias events at 4 center of mass energies:  s= 40,100,175,200 TeV ; ? Used both Isajet and Pythia Monte Carlo Program ? no Detector Simulation (toy or other) taken into account; ? considered only charged tracks; ? mean P T of the event defined as: ? evaluated considering different cuts on the minimum track P T ; ? Event particle density:

14. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Rapidity Distributions Pythia 6.129  Arb. Units Arb. Units

15. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Isajet 7.51 Rapidity Distribution  Arb. Units Arb. Units

16. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Rapidity – Pythia vs Isajet  s=40 TeV  Arb. Units Arb. Units

17. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Rapidity – Pythia vs Isajet  s=100 TeV  Arb. Units Arb. Units

18. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Rapidity – Pythia vs Isajet  s=200 TeV Arb. Units Arb. Units 

19. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone PT Distribution of Charged ParticlesCME <PT><PT><PT><PT>  s= 40 TeV 0.45 GeV/c  s= 100 TeV 0.49 GeV/c  s= 200 TeV 0.53 GeV/c Pythia 6.129

20. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Charged particles P T > 1.0 GeV/c P T > 5.0 GeV/c Pythia 6.129 any P T

21. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Energy Flow 10 3 10 2 10 1 10 0 -10 -8 -6 -4 -2 0. 2. 4. 6. 8. 10.  Energy [GeV] Almost all the Energy is in the Forward Region of  Energy Flow, 100 TeV, 1 Event

22. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Average Number of Charged Tracks 100 10 10.01.1 1 10 100 1000  s [TeV] Charged Multiplicity Pythia 6.129 VLHC = 125 (@ 100 TeV) = 125 (@ 100 TeV)

23. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Number of tracker “elements” ? for 100-200 TeV of CME the expected number of tracks is: N trk ~ 50 x 100 = 5x10 3 (interactions per bunch crossing) ? For reasonable reconstruction/triggering, occupancy below 1% is needed: is needed: N Elem ~ 5 x 10 3 x 10 2 = 5x10 5 Elements/Layer ? A number of Layer > 20 is needed: N Elem ~ 5 x 10 5 x 2x10 = 10 7 number of tracker “elements”

24. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Number of tracker “elements” ? special low luminosity runs are necessary to avoid multiple interactions; interactions; ? in principle such a tracking system should be able to reach reasonable high values of Z. reasonable high values of Z. How trustable are these MC Simulations ?

25. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Mean transverse momentum vs multiplicity CDF Data

26. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Mean Transverse momentum vs multiplicity (MC)

27. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Simulated and Reconstructed inclusive distributions poorly match the Experimental Data (CDF MB @ 1.8 TeV); The shape of the vs multiplicity correlation is roughly reproduced, But values are considerably lower than the measured ones. How well PYTHIA do ?

28. 4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Conclusions ? c ross sections and multiplicities changing with energy increase very slowly; ? M ultiplicity distributions have long non-Gaussian tails; ost of charged tracks are low momentum: <pT> ~ 0.6 GeV; ? @ 100 TeV Pythia predict a mean charged track multiplicity of 125; ? A? A? A? All the studied parameters and distributions are used to evaluate the behaviour of the Monte Carlo… we could see surprizes at very high energy.