1

Why Spend Time Annihilating Matter with Anti-matter?

Rolf-Dieter Heuer leaves DESY (again) to go to

CERN (again)

Hamburg

5 December 2007

Albrecht Wagner, HamburgRDH

matter anti-m

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A leptonic love affair - e+e- colliders

• Born 1948

• The very early history (DESY-Heidelberg) 1974-1977 PhD HD

• The early history (Jade) 1977-1983 Postdoc HD

• The not so recent past (OPAL) 1984-1999 Staff CERN

• Preparing the possible future (ILC) 1998-2008 Prof HH

• Since Dec 2004 Director of Research for Particle and Astroparticle Physics

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The Early Days of e+e- Physics

Is this excess real, what is it?

Everything started with a discrepancy:

1973

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The Past and Future Role of e+e- Colliders

Rolf starts his thesis

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The Power of e+ e- Colliders

• well defined production process, simple kinematics

• precise knowledge of quantum numbers in initial state

• energy and momentum of all partons known

• energy of system can be varied

• precise (<%) knowledge of the cross sections

• low background

• polarisation of e- and e+ beams possible

e+

e-

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DESY/HD and Jade at DORIS/PETRA

PETRA

1974 proposal

1978 first events

13 < E < 47 GeV

DORIS

1974 first events

3 < E < 10 GeVDESY-HD

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A Precise Measurement of the -Mass

W. Bartel, P. Dittmann, P. Duinker, J. Olsson, L. O'Neill, D. Pandoulas, P. Steffen, U. Fritscher, J. Heintze, G. Heinzelmann, R.D. Heuer, H. Rieseberg and A. WagnerDESY, Physikalisches Institut der Uni Heidelberg,

Thesis of Rolf: (1977)

Neutral decays of the ’ (3.7) Resonance

BR (’ -> neutral (not J/)) = (2.0 +- 0.8)10-3

m = 1.787 + 0.010 – 0.018 GeV

From a fit to the energy dependence of the cross section

Today: m = 1776.69 +- 0.18 +– 0.15 MeV

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Detector and Measurement

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Construction started in 1976 thanks to H. Schopper and G.A. Voss

The project advanced very fast

Construction completed in 1978, 6 months ahead of schedule

First stored beam in July 1978

Five experiments approved - CELLO, JADE, Mark J, PLUTO, TASSO

With PETRA DESY became international

PETRA Construction

Competition with SLAC (PEP)

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The Detector Layout Essential features:- Large solid angle- Excellent tracking- Good energy measurement- Muon detection

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The Proposed Physics Programme

LoI for JADE:

• Measurement of magnitude and energy dependence of hadronic cross section

• Search for new quarks and leptons (mainly top)

• Measurement of magnitude of electroweak interference

• Study of hadronic final states, prove existence or non-existence of jets

• Is QED correct at high energies?

• Study decays of heavy quarks

• Study photon-photon interactions

…but nothing about gluons

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Discovery of Gluon

Field theory predicted that the outgoing quarks radiate field quanta (gluons)

The probability for radiation is ~ s(q2)/which at PETRA energy is ~ 10%.

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Discovery of the Gluon

PETRA as test bed of QCD:

quarks radiate gluons

-> 3 jet events

planar events with 3-jet structure

one sided jet broadening

The quantum of the strong force was discovered and studied at a lepton collider

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Lepton Photon Symposium 1979

All 4 PETRA experiments presented their data.

The conclusion of all four experiments (JADE, Mark J, PLUTO and TASSO) was very similar:

To cite S. Orito (JADE, Tokyo):

“Quantitative as well as qualitative properties of the planar 3-jet events agree in detail with the predictions based on the gluon bremsstrahlung process and the suggested fragmentations. This strongly suggests hard gluon bremsstrahlung as origin of the planar 3-jet events.”

Lepton-Photon Symposium, Fermilab 23– 29 August 1979

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Most cited PETRA papers

1) W. Bartel et al., R.D. Heuer, EXPERIMENTAL STUDIES ON MULTI – JET PRODUCTION IN E+ E- ANNIHILATION AT PETRA ENERGIES.

Z.Phys.C33:23,1986. (cit. 660 times in HEP (SPIRES-SLAC))

2) R. Brandelik et al., EVIDENCE FOR PLANAR EVENTS IN E+E- ANNIHILATION AT HIGH-ENERGIES.

Phys.Lett.B86:243,1979. (412)

3) S. Bethke et al., R.D. Heuer, EXPERIMENTAL INVESTIGATION OF THE ENERGY DEPENDENCE OF THE STRONG COUPLING STRENGTH.

Phys.Lett.B213:235,1988. (411)

Discovery of the Gluon, the particle mediating the strong force

1995: EPS HEP Prizes for Gluon discovery

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Muon Asymmetry

Interference of electromagnetic and weak interaction leads to a forward-backward asymmetry

GeVZM )(71)(15

570

10

232

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Search for the Top Quark

Many theoretical predictions expected the top-quark to lie ‚just around the corner‘

scan for narrow resonance

as expected for udscb + QCD corr.

22.088.3 R

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JADE

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JADE

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JADE

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Then Rolf went to CERN …

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… to join OPAL at LEP

• Detector pictures

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OPAL – Main Physics Aims (from LoI 1982)

• Observation of Z0 (mass, BR, width …)• Measure number of generations• Test of SM

– Precise study of electroweak interference– Weak decays of heavy quarks– Search for the Higgs

• Search for new physics– New flavours– New heavy leptons– Supersymmetry – Technicolour

• Study of QCD

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The Team

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Building the Jet-Chamber

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LEP Events

q q q q q q

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Cross sections

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Three Generations

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Electroweak Precision Tests

The SM is tested to unprecedented accuracy

No deviations observed

precision data tell us something about mass range not accessible today

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Search for the Top Quark

Indirect determination of the top mass

possible due to

• precision measurements

• known higher order electroweak corrections

)ln(,)( 2

W

h

W

t

M

M

M

M

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Rolf’s Roles in OPAL

• Building the Jet Chamber with the German universities (coordinator)

• Run coordinator• Spokes Person• Motivating people …

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The possible future

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A memorable event

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The TESLA Project

Superconducting electron-positron linear collider

with

integrated X-ray laser

http://tesla.desy.de

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The Key Questions of Particle Physics

• What is matter ?• What are the forces ?• Can quantum physics and general relativity be united?• What happened in the very early universe ?

Where do the experimental answers lie?• At highest energies Large Hadron Collider construction finished at CERN

• In precision measurements Electron-Positron Collider TESLA project -> ILC

Physics and experience teach us that we need these different tools to answer these questions and that they complement each other

The Road Map of Particle Physics

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Extra Spatial Dimensions

Emission of gravitons into extra dimensions

+ emission of (or one jet)

measurement of cross sections at different energies allows to determine number and scale of extra dimensions

cross section for anomalous single photon production

Energy

= # of extra dimensionse+e- -> G

•In how many dimensions do we live?

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The Site Preparation

Two independent radiological evaluations

Preparation of environmental impact study

Agreement between the states Schleswig-Holstein and HH for joint legal procedure

Regular information of all persons living along TESLA

Preparation of “Planfeststellung”

Research Campus Ellerhoop

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TESLA … followed by the ILC

• After the decision of the German Government to build the XFEL and PETRA and to support DESY in the further preparation of the ILC, Rolf was active in many ways in promoting the ILC:

– Leading the parameter group of the ILCSC– Leading a very thriving group at the University of HH

and DESY– Organising LCWS 2007– Giving many talks– Helping build the bridge to CLIC– Etc., etc.

– Driving a car with the number plate HH-LC …..

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Good by and good Luck – the end of a love affair?

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Many Thanks, Rolf

For your strong support of particle physics• In the world• In Europe• In Germany (Helmholtz-Allianz)• At DESY