Post on 22-Jan-2016
description
transcript
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