talk to cern students, 13 august 2004 happy birthday cern 50 herwig schopper

Talk to CERN Students, 13 August 2004

Happy Birthday

CERN50

Herwig Schopper


Council argued that CERN should make history,not talk or write about it *

But CERN is such a unique European success (1. European organisation) that one should learn from 50 years of experience

I shall talk about

History

Successes and Failures


Two initiatives in parallel:

1.physicists:join European forces to be competitive with US, in particular for large facilities E.Amaldi, P.Auger, L.Kovarski, F.Perrin1950 report by Kovarski: establish intergovernmental centre, „essentially scientific“

2. Political initiative: European Movement

European Cultural Conference, Lausanne 8-12 December 1949

bring Europeans together after war

170 people from 22 countriesMinisters, senators, member of parliaments,others D. de Rougemont (Suiss Writer), R.Dautry ( F Minister), *

Foundation of CERN


The two initiatives combined at 5. General Conference of UNESCO in Florence, June 1950

-Rabi’s Resolution 7 June 1950 addressed to DG UNESCO could be considered as ‘conception’ of CERN (or real birth??)

At CERN 30. Anniversary 1984

Rabi’s speech: CERN peaceful compensation for building bomb

“CERN was founded less then ten years after the bomb was made. I feel that the existence of the bomb …had a large part in making CERN possible. ....Europe had been the scene of violent wars..for 200 years. Now we have something new in the founding of CERN”

“I hope that the scientists at CERN will remember that they have other duties than exploring further into particle physics. They represent the combination of centuries of investigation and study… to show the power of human spirit. So I appeal to them not to consider themselves as technicians …but .. as guardians of this flame of European unity so that Europe can help preserve the peace of the world.”


Agreement to constitute “Council”signed on 15 February 1952 by 11 countries Approval of Convention 1 July 1953, signed until December 1953 by 12 States

Conseil Européen pour la Recherche Nucléaire

« N » is problem

Subsequent submission of letters of ratification to UNESCO DG

Convention comes into force if ratified by at least 7 States: on 29 September 1954 (Birth!!?)

CERN became intergovernmental organisation

who knows what CERN stands for?


Objectives of CERN Promote science and technology (later training)

to make Europe competitive

Bring nations together first in Europe, later worldwide

CERN only lab with both objectives (now also SESAME)

CERN became first European Organisation

Expectations were met in excellent way


1. Choice of site : Proposals:: Geneva (CH), Copenhagen (DK), Arnhem (NL), Longjumeau (Paris)

‚…delegates had clearly been officially briefed to make stiff fight.,

scientific prestige …was clearly rated very high,…

expectation of ..appreciable .. ‘financial gain’

Final decision at 3. Council meeting at Amsterdam October 1952

Geneva: small country, neutrality, nice living conditions

Some Problems at Foundation

Difficulties forgotten today, but start was not easy


Proportional to income and wealth, but how to asses it?

GNP or GNP per capita?

Sweden and CH against GNP/capita (since their GNP/capita 50% higher than UK und F !)

Italy and Yugoslavia in favour

‚...endless and confused discussion..’

2. National Financial contributions

Ben Lockspeiser (Council President) exploded, fed up with

‘shameful horsedealing’

‘Offended, a Swedish Delegate broke down and wept openly’

Final solution: GNP with limit of 25 % maximum contribution


CERN became model for other organisations

in Europe ESO, EMBL

Joint Institute for Nuclear Research JINREstablished for Warsaw pact states in March 1956First organisation following CERN Close cooperation with CERNimportant bridge between West and East during cold warNew role after disappearance of Soviet union New Charter in 1992 Now 18 Member States

SESAME Synchrotronradiation Laboratory near Amman, JordanIntergovernmental organisation like CERN,

Estbalished by UNESCO April 2004 according to CERN model

Presently 7 Members (Bahrain, Egypt, Israel, Jordan, Palistan, Palestine, Turkey,.....Iran, Kuwait, Yemen, UAE)


Basic Physics using large facilities is excellent tool for ‚Science for Peace‘

Laws of physics are valid everywhere

No secrecy in basic science (neither industrial nor military)

Large facilities (accelerators, reactors, detectors, telescopes, etc) need scientific, administrative and

political cooperation (at highest level)

Cooperation creates confidence between people from different nationalities, religions, cultures, mentalities, political systems

Physicists in basic science give priority to science* instead to money Money has only secondary importance, not main motivation, profession is hobby


Examples of Confidence buildingCERN – IHEP (Soviet Union) agreement in 1968became model for IHEP-USA agreementand later model for USA- Soviet union agreement (Breshnev-Ford) (Mirabelle staff, 1. Strike on SU territory)

Disarmament meeting at Geneva in 1980ieswhen in deadlock private meeting (USA,USSR) at CERN unblocked it

(Trivelpiece asked for lunch)

Meeting with Ambassadors of Disarmament Conference‘Avoid collisions between countries, CERN does better’


Science radiates into politics

CERN-JINR,Dubna: only link East-West Germany

L3 chinese from Mainland and Taiwan

SESAME: Israel -Palestine – Iran

Help individualswho have of political, racial or religious problems Orlov (from Sowjetunion to CERN, talk to Petrosyansk) Okun (in SPC, not allowed to come, talk to Chuvilov) Hadizadeh (arrested in Iran, letter to Minister and Chatami, could come to SESAME meetings, now in USA)

Help developing countries


In time where relations between some nations are sometimes characterised by

hatred and violence

it is gratifying that scientists, administrators and politicians are prepared to sit around the same table to discuss scientific projects

Small light in dark times


LEP/LHCSPCPS/ISR

CERN crossing the Swiss-French Border


Memberstates of CERN

Von 12 zu 20 Mitgliedsstaaten

+ Associates USA, Russland, Japan, Indien, Israel,........


Working Style of CERN

Tasks shared between CERN – Users

CERN builds and operates facilities, coordinates exploitation (Technical Competence)

“Service Station”Users come from Universities, national Labs, etc. (about 6000, of which only about 80 from CERN)

(Scientific Competence, Rejuvenation)


Users in whole World


Domains of Success

Accelerators and Storage Rings

Detectors, Information Technology

Large Experimental Facilities (“Experiments”) Coordination

Scientific Results


Why race to higher energies and hence big facilities?

1.The smaller constituents of matter are, the stronger they are bound togetherHeisenberg uncertainty p . R ≈ h/2π„Atom smashers“

2. To produce heavy particles and new states of matter (energy concentrations like after big bang) E = m.c2

Collider Rings


Why are detectors so big?• Momentum measurement in magnetic field B

p . R ∞ B B limited to several Tesla, ∆R limited to 10 to 100 micron=> R must be order of meter for p of several GeV

• ‘Calorimeter’ must contain particle shower of several Radiation length for hadron showers λ about 0.5 m ( ∞ log Energy) => calorimeter length more than a meter

But also precision in determining coordinates!!!!


Accelerators: First Period of CERN: ‚Copy‘

Machine with highest energy in Europe, ‚copy‘ of BNL machine

Proton-Synchrotron PS Protons 28 GeV (circumference 200 m), Main objective at foundation of CERN,

Start of operation 1959, workhorse for many years In operation still today, pre-accelerator for all other machines


John Adams with Vodka-Bottle from JINR

to empty when PS more than 10 GeV

PS reached 24 GeV on 24 November 1959


Second Period of CERN: Unique Facility

ISR Intersecting Storage Rings Proton-Proton Speicherring

„Collider“

Two deformed Magnet - Rings, cross in 8 points,

Counter-rotating Proton beams with 31 GeV (up to 60 A).


Layout of ISR


Fixed Target <=> ColliderAdvantage of Colliders:Car driver knows the effect of head –on collisions

- Useful Energy is Center of Mass EnergyES = 2 x Ekin (kinetic Energy Ekin)

ISR ES = 62 GeV

Particle hitting target at rest ES ~√Ekin

ISR equivalent Energy 2000 GeV!

- Storing beams increases probability of collisions

Disadvantage of Colliders:-No secondary beams of other particles


ISR Intersecting Storage RingsMany Records in the art of accelerator building

Storage time of several weeksonce Antiprotons stored for 1000 hours New limit for lifetime of antimatter

New window für physics

ISR was unique in World, (no successor up to now, only LHC)

1984 difficult and painful decision to stop it, ( to find ressources for LEP)


Next step:Super-Proton-Synchrotron SPS

Proton-Accelerator Energy 400 GeV

To be able to compete with American Fermilab 1000 Magnets in Tunnel with about 7 km circumference

Failed almost since new sites were proposed in 12 states,but no agreement

Solution CERN I und CERN II , 2 DGs only 1981 full unification of lab

-started operation 1976Important Extension of Site to France


John Adams and Willibald Jentschke in SPS Tunnel 1973


Super-Proton Synchrotron SPS

Powerful secondary beams

two new experimental areas, West and Nord (in France)Muon-, Pion-, Neutrino – beamsPolarised beams and Targets

Heavy- Ion Acceleration AU- nucleiInvestigate Quark – Gluon Plasma (first observation ?) *

SPS still in operation for fixed target Physics and pre-accelerator for (LEP)/LHC


Period of Matter – Antimatter Colliders

Protons – Antiprotons in SPS ring 2 x 400 GeV

SPPS (third mode of operation of SPS) (proposal Rubbia) ES = 800 GeVEquivalent energy 155 000 GeV , Even today not realisable!

ButAntiprotons difficult to produce‚stochastic cooling‘to homogenise direction and energy(against Liouville‘s Theorem)Maxwell‘s Dämon ?

Simon van der Meer (Nobelpreis 1983)

Particles – Antiparticles in same Ring


Disadvantage: complicated events

Advantage: Protons easy to acceleratelimited by magnet field strength and radius

Protons not elementary, contain 3 Quarks + Gluonen

e+ e- collider

Advantage: give clean events, high event rates e+ and e- have no inner structure

p – p collider

Quarks

Gluons

Disadvantage: acceleration of electrons very difficult in ring synchrotron radiation losses ~ E4/R


LEP Large Electron – Positron Collider

Proposal by international community in 70‘ties :

Elektron-Positron Collider with 50 to 100 GeV per beam(after succes of ADONE, PEP, DORIS, PETRA, TRISTAN)Look for W and Z, Supersymmetry, top.

cost optimisation gives R ~ E2

=> circumference about 30 km

?Ring or two colliding lineacs? LEP last circular e+e- facility

Such a facility only realisable as World Machine?Could be built at CERN?


LEP ApprovalVarious proposals with „oscillating“ energy and radius in the late 1970iesCERN-Council accepts new LEP Design in June 1981Tunnel with circumference of 27 km

Conditions: constant budget (low level) (resign !?) ‚stripped down LEP’ minimum of components at start Phases

LEP 1 2x 50 GeV LEP 2 2x 100 GeV 3. LHC (Tunnelcircumference) Workshop March 1984

Lausanne Time is contingency (indeed one year delay) stop many existing facilities even when still interesting

Groundbreaking 1983 Start up 1989 End 2000


CERN Budget


LEP Positions

Top secret


Water in LEP Tunnel


Mrs.Thatcher at CERN 1983


Paul Johannes II at CERN


LEP Groundbreaking 1983

Presidents Aubert (CH) and Mitterand (F)


LEP ConstructionConventional machine ??new Technologies (examples)

oabout 3000 bending magnets (iron sheets with concrete in between), mass quality control, installation

o highfrequency accelerating cavities, first copper, later superconducting Nb

onew Getter-Pumps, extreme highvacuum in 27 kmosurvey procedures (Laser, Satellites) for installation of

magnets and other components (Tolerance tenths of mm for distances up to 10 km )

Not size of tunnel impressive, But size combined with precision. Toleranz circumference = ± 2.8 cm, measured 0.8 cm


LEP Tides


LEP Tunnel


LEP Operation

LEP 1: beam energy around 50 GeV for 7 years „Z- Factory“ millions of Z- particles produced (UA1 und UA2 had only handful events for discovery)

LEP 2: from 1996 energy increase in steps with SC cavities (Nb massiv and coated)During last months of 2000 achieved 104.5 GeV/beam Energy concentration as 10-10 s after Big Bang of cosmos

During 11 years LEP worked excellently

Last circular e+e- machine => NLC


Detectors, Data Handling

Bubble chambers Gargamelle, BEBC,... Develop technology of superconducting magnets

Multiwire chambers (G. Charpak Nobelpreis)many applications, customs

„Calorimeter“ Sampling Total-Absorptionscounter STAC, energy measurement without magnetic field, neutral particles *

Crystal counters for Gamma, 10000 cristals (application in medicine)

Silicon-Strip Detectors a few Precision

Data handling:Collection, reduction, storage, analysis, transfer

WWW developed for LEP - Experiments


Large „Experiments“

Not „Experiment“, project in itselfManagement success to organise themInstitutions on their own: several hundered scientists, administrators,...Components from many Labs in many countries(coordination, fitting together, time schedule)Industry like, but international, no management power!

Modell for scientific, technical and financial cooperation („resource committees“)

„LEP Model“ continued with LHC experiments

1000 to 2000 scientists


LEP ExperimentsALEPH,ALEPH, DELPHI,DELPHI, L3L3 und und OPAL OPAL *International collaborations with hundreds of scientists from countries with different political systems, various traditions, mentalities and religions

Components fabricated in many countries

Cost of each detector 100 to 500 millionen CHF

Hundered to several hundered scientists


CMS

ATLAS

ALICE

LHCB

coin


Scientific Success

Progress in Science by:

1. Spectacular Discoveries

2. Tedious work in detail

3. Missed opportunities

All equally important!


Some (most important?) questions of Particle Physics

1.Elementary building blocks of Matter?Quarks, Leptons (charged, Neutrinos) Supersymmetric particles, other ?What determines Masses?

2.Which Forces in nature and their properties?Carrier: Photon, Gluon, W, Z (‚heavy Light‘), graviton

Great Unification of Forces ?


Periodic Systematics of Elementary Particles

Charges: Electrical: +2/3 -1/3 0 -1 Weak : flavour in columns Strong : colour

Strong force No Strong force


Vector Bosons (Spin 1)Carrier of Forces by exchange

Interaction Boson Discovery

Electromagnetic Photon Photoeffect

no charge Compton effectStrong Gluon DESY

1976colour

Weak W+, W- Z CERN

1983weakcharge

Photons do not interact

Gluons interactW and Z interact


New Paradigma• Since Democritos, Galilei, Newton:

External building blocks with forces between them explain phenomena in natureOnly building blocks changed during last 300 years(molecules, atoms, nuclei, protons and neutrons, quarks and leptons)

Eternal change by different arrangements of blocks

• Present most fundamental recognition:Symmetries and their (spontaneous) breaking are basis of understanding of NatureNo undestructible building blocks (Newton)

From Democritos to Plato?


Spectacular Successes of CERN

Large transvers momenta at ISR 1972

Indication of partons inside nucleon

Neutral currents (Z) of weak interaction Gargamelle 1973 (Lagarigue)

W and Z with SPPS, UA1 und UA2 1983 (Rubbia, van der Meer)

Gluon discovered at DESY


Pion Production with large transverse momenta at ISR

Indication of pointlike partons


Gargamelle Heavy Liquid Chamber

Filled with 16 tons of

Freon


Neutral Currents

Gargamelle 1973

Elastic Scattering+ e + e

Elektron Bremsstrahlung-cascade


UA 1 Detektor

„Hermetic“ Detector


UA1 Z e- + e+


Z – event in OPAL at LEP


Discovery of W and Z Press Conference 1983

visa


‚Work in detail‘

Impossible to mention here all relevant results of CERN

Nucleon-Structure (with polarisation)

Neutrino –Scattering (except neutral currents)

CP-Violation (LEAR)

K and B Oscillations

Quark-Gluon –Plasma

Exotice Atoms and nuclei, Anti-hydrogen

g –2 of Muon


Missed Opportunities

Second Neutrino PS 1961 BNL

J/ at ISR 1972 1974 BNL,SLAC

at ISR 1972 FermiLab 1977

Experience, hard work and perseverance do not suffice

A little bit of luck is also needed !!


LEP ResultsNo Sensations (TOP, SUSY, Higgs)

But fundamental results from detailed work

Weak Interactions• Precision measurements

turned HEP into Precision Physics (< 0.5 %)

• Standard-Modell is renormalisable Fieldtheorie Radiation corrections (cp. Lambshift) (TOP - Quark),

• 3 Kinds of Neutrinos

• Coupling W-Z-Z


Linenwidth and Hight give No. of Neutrino kinds

(Nν = 2.985 ± 0.008)

Position of Maximum

gives


Standard Model with

Precision < 1%

confirmed


Existence of coupling

between W-Z


Strong and other Interactions

1. 3- and 4 – Jet Physics Quark-Physics , Gluon -Gluon – coupling

2. Running coupling constant S (Quark –Confinement Asymptotic freedom)

3. Limit for Higgs-Mass (discovery with LHC)

4. Indication for Supersymmetry Gand Unification ?


LEPmortHS

LEP Fest October 2000


The Secret of Success scientific quality and competence count

(no „by-in“)

no national or other quota for employment of personel or adjudication of industrial contracts (no „just retour“)

no secrecy, cooperation in spite of competition

no discrimination of nationality, race, origin, religion *

ambition to be at frontier of world excellence, in spite of high risks

Memberstates in favour of pragmatic solutions avoiding purely political aspects


Future of CERNGuaranted with LHC Fundamental discoveries likely and needed for HEP

CERN excellent Laboratoryavoid bureaucratisation, too little staff

Many difficulties not surprisingsimilar as with LEPe.g. bell shaped spending profile with constant

Finances will not be end of HEP, but long time scales are worrisome!!

Interest of young scientists !!!

talk to cern students, 13 august 2004 happy birthday cern 50 herwig schopper

Documents

cern students

objectives of cern

conception of cern

cern possible

cern peaceful compensation

european forces

flame of european unity

unique european success