Task A: ZEUS 2005-2006

N. Brummer, L.S. Durkin, A. Lee, T.Y. Ling

O.S.U. History on ZEUSJoined ZEUS 1985 One of U.S. ZEUS founding members

Designed and Built Optics for ZEUS Barrel Calorimeter

87,000 Scintillator Tiles5000 Wavelength-Shifter Light Guides and Correction Masks

Designed and Built FastClearTrigger Processor

Fast (15sec) Cluster Finder Electron Identification Kinematic Variables E-PZ

Beam Gas Rejection

Manufactured Optics forBarrel Calorimeter Presampler

Group History on ZEUS (cont.)

Administrative U.S. ZEUS Spokesman3 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 !

Personnel 2005-2006

OSU ZEUS Effort is Bare Bones

- Nicole Brummer (100%) at DESY Trigger Coordinator(2002-2004)

- Grad Student Albert Lee at DESY

Background Problems fixed !

• Synchrotron radiation fixed• e-gas decreased• p-gas decreased

HERA I (8 years) 193 pb-1

HERA II (1.5 years) 203 pb-1

• New Data has Polarized Electron/Positrons

• 4X increase in e-p Data

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

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 ViolatingSUSY particles

Nicole Brümmer

Spin-Dependence of Charged CurrentCross Sections

Albert Lee(Thesis), Nicole Brümmer

centre-of-mass energy squared:s = (k + p)2 = 4 Ee Ep

Q2 = -q2 = - (k – k‘)2 = s x yfour-momentum transfer

x = Q2 / (2Pq) Bjorken-xmomentum fraction of struck parton

y = (Pq)/(Pk) Inelasticityrelative energy transfer to the proton

HERA Kinematics

30 GeV e±

900 GeV pC.M. 315 GeV

Deep Inelastic Scattering

Charged Current

Neutral Current

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

Nichol Brummer, SUSY-2005 Durham

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)

t

PtPT exp1)(

at HERA =30minPaverage=40% (depol. effects)

)()1()(, ePe ccpolcc

With one years data should be able to set limit MW(R) < 400 GeV

The Cross section depends on polarization. OneSearches for e.g. WR and tests Standard model.

Charge Current Deep Inelastic Scattering

Charge Current Cross Section

This analysis will be Albert Lee’s Ph D Thesis

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