ZEUS and HERA (Physics at small distances)

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ZEUS and HERA(Physics at small distances)

• true as haze

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30 June 2007
Best wishes from all your ZEUS colleagues on this
special occasion
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27 Feb. 1986
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A Drama in 3 Parts with a Prolog

• Prolog Dreams and Politics
• Day 1 Planning and Building
• Day 2 Running and Measuring
• Day 3 Analysing and Publishing

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Prolog

• Dreams and Politics
• Prehistory 1984

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The Dream
a Lepton-Proton Double Ring Collider Ecm gt
300GeV Ep 820 GeV (? 920GeV) Elepton 30 GeV (?
27.5GeV) ? Spatial resolution 10-18m
Björn H. Wiik 1937 - 1999
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The Dream
SLAC 1969
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1984 HERA Go ahead
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Day 1

• Planning and Building
• (1984 1991)

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e/ e- Protons
Energy nominal (GeV) Energy nominal (GeV) 30 820
Energy range (GeV) Energy range (GeV) 10 35 300 1000
Luminosity Luminosity 1.5 x 1031cm-2s-1 1.5 x 1031cm-2s-1
Circumference Circumference 6.3 km 6.3 km
Magn. Field (T) Magn. Field (T) 0.165 4.7
Beam current (mA) Beam current (mA) 58 160
Bunches Bunches 200 200
e/ e- polarized e/ e- polarized e/ e- polarized e/ e- polarized
Petra Injection (GeV) 12 12 40
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ZEUS Proposal
March 1986
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High Q2 CC Interactions
Energy Containment/Muons
Excellent Hadronic Energy resolution
Tracking/Vertexing
Missing energy Hermeticity
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ZEUS Detector

• Asymmetric
• Compact
• High energy resolution
• general purpose tracking

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1984 1987 Civil Construction
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1988 1991 Detector Construction
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ZEUS CTD(untouched from 1992 2007)

• Longevity
• Robustness

• Excellent XY resolution
• Z Measurement
• Triggering
• Homogeneous

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The CTD moves into ZEUS (is moving out again next
week)
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Day 2

• Running and Measuring
• (1992 2007)

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Björn Wiiks entry in the HERA log (19 Oct 1991)
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ZEUS measuring
Early 90s
First collisions 31 May 1992, 1740
30 June 2007
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Running The Official Story
ep
HERA II
long. polarization
e-p
HERA I
ep
e-p
ep
Great Success 0.8 fb-1 delivered/ 0.5 fb-1 gated
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Day 3

• Analysing and Publishing
• (1992 Future)

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Paper Statistics
185 papers so far
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The first paper

• 227 µb-1
• 7 h of running
• Ca. 50k events
• Publ. Sept. 92

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The first F2 result

• 23.7 nb-1
• Ca. 4 Mio evts.
• Publ. Aug. 93

F2 rises very fast at low x
Scaling violations
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F2 today
This is a triumph for experiment and for
perturbative QCD
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F2 today
Unprecedented precision due to cross calibration
of detectors
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HERAPDF 0.1
High precision HERA PDFs translate into precise
SM predictions at LHC
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W/Z Pair Production at LHC
A. Cooper-Sarkar E. Perez Presented at HERA and
the LHC 26 28 May 2008
Uncertainties at 3 level!
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NC CC _at_ high Q2
The classic HERA legacy plots
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Ultimate precision
RQ lt 0.6 x 10-18 m (1/1000 of the proton radius)
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Rapidity Gaps/Hard Diffraction
?max, the most forward energy deposit

• 10 of DIS events are rapidity gap events
• publ. July 1993

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HERA Diffraction Industry
MX Method
Tagged Protons
Rapidity Gaps
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Hadronization Rattling the cage(and putting the
CTD through its paces)
publ. Jan 1995
Quarks hadronize the same way in ep and in ee-
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Directly peeking in Prompt photons
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Finale(the story is not over!)
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What have we (not) seen?

• No Physics beyond SM
• Excited fermions ?
• Gravitons ?
• Stops ?
• Finite quark radius ?
• Large extra dimensions ?
• Leptoquarks ?
• No exceptional rates
• Lepton Flavour Violation ?
• Single tops ?
• Single isolated leptons ?
• Multi-leptons ?

• Exotic hadrons ?
• Strange Pentaquark ?
• No charmed PQ ? !
• Glueballs ?
• Marvels of the SM
• A deep view into the proton
• Miraculous hard diffraction
• Asymptotic freedom
• EW physics in the spacelike regime
• ?

We should all wish the LHC good luck!
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A possible Glueball candidate
all ZEUS data

• Most significant (5s) observation of f0(1710)
• Thank you very much David for your help!

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Thanks David
true as haze
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