1. Task A: ZEUS
N. Brummer, L.S. Durkin,
A. Lee, 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. Personnel 2005-2006 OSU ZEUS Effort is Bare Bones
- Nicole Brummer (100%) at DESY
Trigger Coordinator( )
- Grad Student Albert Lee at DESY

5. HERA I (8 years) 193 pb-1 HERA II (1.5 years) 203 pb-1
Background Problems fixed !
Synchrotron radiation fixed
e-gas decreased
p-gas decreased
HERA I (8 years) pb-1
HERA II (1.5 years) 203 pb-1
New Data has Polarized Electron/Positrons
4X increase in e-p Data

6. 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

7. O.S.U. Physics Analysis 2000-2005 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

8. 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

9. Deep Inelastic Scattering
Neutral Current
Charged Current

10. 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

12. Nichol Brummer, SUSY-2005 Durham

14. 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

15. Charge Current Deep Inelastic Scattering

16. Charge Current Cross Section
This analysis will be Albert Lee’s Ph D Thesis

17. 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