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 !

VLHC the Very Large Hadron Collider

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$) VLHC TESLA/LC 2020 US Expenses

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

Fermilab MichiganLake Tevatron

why Fermilab ?

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

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

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 mb mb mb mb mb mb mb mb Low P T Processes ---- Inelastic Cross Section mb mb mb mb mb mb mb mb Total Cross Section---- PYTHIA 6.129

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

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

4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone ? Generated 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:

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

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

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

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

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

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

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 any P T

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

4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Average Number of Charged Tracks  s [TeV] Charged Multiplicity Pythia VLHC = TeV) = TeV)

4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Number of tracker “elements” ? for 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”

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 ?

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

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

4 th International Workshop on VHMP, Alushta 2 June 2003 Carmine Elvezio Pagliarone Simulated and Reconstructed inclusive distributions poorly match the Experimental Data (CDF 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 ?

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.