1. Task A: ZEUS
N. Brummer, L.S. Durkin,
T.Y. Ling

2. O.S.U. History on ZEUS Joined ZEUS 1985
One of U.S. ZEUS founding members
Designed and Built Optics
for ZEUS Barrel Calorimeter
87,000 Scintillator Tiles
5000 Wavelength-Shifter
Light Guides and
Correction Masks
Designed and Built FastClear
Trigger Processor
Fast (15sec) Cluster Finder
Electron Identification
Kinematic Variables E-PZ
Beam Gas Rejection
Manufactured Optics for
Barrel Calorimeter Presampler

3. Group History on ZEUS (cont.)
Administrative
U.S. ZEUS Spokesman
3 Physics Coordinators
Run Coordinator
Trigger Coordinator
Post-Doctoral Fellows
B. Bylsma, C.L.Kim, C. Ginsburg,
N.Brummer K. McLean, B. Murray,
S. Park, I. Park, D. Acosta
Physics Chair Assoc. Prof Assoc. Prof.
Korea U Kyungpook U U. of Florida
3 faculty Positions out of 9 postdocs !

4. HERA I (8 years) 193 pb-1 HERA II (2.5 years) 403 pb-1
Background Problems fixed !
Synchrotron radiation fixed
e-gas decreased
p-gas decreased
HERA I (8 years) pb-1
HERA II (2.5 years) 403 pb-1
New Data has Polarized Electron/Positrons
4X increase in e-p Data

5. Rate Increase: Fast Clear is now an Essential Component
Fast Calorimeter Cluster
Finding Trigger
E-Pz,PT, Beam Gas, Electron
Clusters, Jet Clusters
Abort fraction 20-30%
WWW run monitor written
Trigger works stably
Better Modeled in MC than
CFLT

6. HERA Kinematics 30 GeV e± 900 GeV p C.M. 315 GeV
centre-of-mass energy squared:
s = (k + p)2 = 4 Ee Ep
Q2 = -q2 = - (k – k‘)2 = s x y
four-momentum transfer
x = Q2 / (2Pq) Bjorken-x
momentum fraction of struck parton
y = (Pq)/(Pk) Inelasticity
relative energy transfer to the proton

7. Physics with a Polarized Electron Beam
Standard Model
Neutral Current
left/right handed particles
interact unequally with Z0
Charged Current
left-handed particles only
HERA
Transverse Polarization
builds up naturally at HERA
(Sokolov-Ternov effect)
at HERA =30min
Paverage=40% (depol. effects)
The Cross section depends on polarization. One
Searches for e.g. WR and tests Standard model.
With one years data should be able
to set limit MW(R) < 400 GeV

8. Charge Current Cross Section

9. Charge Current Deep Inelastic Scattering

10. HERA will shutdown forever June 30, 2007
FL Measurement
HERA plans to run low-energy collision in 2007
460 GeV p GeV e
Naïve Quark Model: Hadrons quarks have P(T)=0
QCD radiation introduces quark P(T)
Theoretical Predictions Vary Wildly

11. In July we sent a note resigning from the ZEUS
Collaboration Effective December 2006
Decision a Finacial one, we did not have the funds
to support Nichol Brummer.
Collaboration begged us to stay on. The OSU Fast Clear
essential to low energy run (rejects 30% of background).
We agreed to stay on if one-shot money could be found to
cover Nichol’s Salary for 6 months.

12. Trigger Summary – ZEUS Collaboration Meeting Plenary Session
FL, Low Energy testrun 59937
STD High Lumi
Loose NC DIS slots 37, 46
EmPzHi 30 GeV
Normal Run
Low Energy Run
0: NC DIS RCAL
1: NC DIS B/RCAL
2: PHP
3: CC
4: EXO + misc
5-8: B/F/Bac/R MU
9: any MU
10: random, calib, ‘passthrough’
13: Abort/Accept=75%
11: AbortCond/Accept=55%
Dominant FCLR Cuts
BG Cut
E-Pz >30 GeV
FL/Low energy running: FCLR very effective
FCLR can provide rejection factor 4.5, in stead of current factor 2.25!

13. HERA’s Legacy

14. The End

15. O.S.U. Physics Analysis 2000-2006 Structure Function and High Q2
Camille Ginsburg (Physics Coordinator)
Contact Interactions
Jason Gilmore (Thesis)
Limits on Production of R-Parity Violating
SUSY particles
Nicole Brümmer
Spin-Dependence of Charged Current
Cross Sections
Albert Lee(Thesis), Nicole Brümmer

16. Deep Inelastic Scattering
Neutral Current
Charged Current

17. High Q2 NC/CC DIS Cross Section
Electroweak unification scale ~104 GeV2
At Q2>104 GeV2 NC=CC
Statistically limited at high x/high Q2
Cross sections sensitive to sea/valence quark
densities and electroweak parameters

18. Nichol Brummer, SUSY-2005 Durham

20. Physics with Polarized Beams
Standard Model
Neutral Current
left/right handed particles
interact unequally with Z0
Charged Current
left-handed particles only
HERA
Transverse Polarization
builds up naturally at HERA
(Sokolov-Ternov effect)
at HERA =30min
Paverage=40% (depol. effects)
The Cross section depends on polarization. One
Searches for e.g. WR and tests Standard model.
With one years data should be able
to set limit MW(R) < 400 GeV

21. Future 2005-2007 ZEUS Operations will end in mid-2007
ZEUS has produced quality physics in the last fourteen years.
HERA has doubled our data sets in the last 1.5 year.
The Ohio State Group will continue to monitor and
maintain the ZEUS Fast Clear
With the new luminosity this group will continue to
study high Q2 high x physics and new Electron
Spin Physics