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ZEUS Status Report: June 1999

ZEUS Status Report: June 1999. A Word on the Spring 1999 e - p Luminosity Run Performance Physics Highlights From Recent Analyses A(nother) Guided Tour Along Q2, including Photoproduction of jets and of charm Deep Inelastic Scattering (DIS) production of charm and dijets

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ZEUS Status Report: June 1999

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  1. ZEUS Status Report: June 1999 • A Word on the Spring 1999 e-p Luminosity Run Performance • Physics Highlights From Recent Analyses • A(nother) Guided Tour Along Q2, including • Photoproduction of jets and of charm • Deep Inelastic Scattering (DIS) production of charm and dijets • Inclusive Scattering at the Highest Q2 • Progress on Approved Tracking Upgrades • Straw Tube Tracker • Microvertex Detector • Bring on the Positrons ! Danny Krakauer Argonne National Laboratory ZEUS Report : 47. DESY PRC

  2. Summary of the 1999 e - p Run Ldt = 11.4 pb-1 • Rapid ramp up to nominal efficiency (as per 1996/1997, w/ short Winter break) • Achieved  70 % efficiency relative to useful lumi. • Improved over 98, approaching 97 record. • Dealt with Coasting Protons problem at the trigger level • Two-Person shift crews ZEUS Report : 47. DESY PRC

  3. About to embark on tour of (quite) recent ZEUS results • A very broad and deep program, that’s also a lot of “fun”. • Some statistics to illustrate the activity: • From January - August, ZEUS physicists will give 105 invited or contributed conference presentations. • Since last PRC meeting, 5 EPJC articles have been submitted/accepted, 4 more have passed collaboration “readings”, and xmore are advanced to pre-reading stage. • Last week, an exciting collaboration week with over 30 physics presentations and extended discussions. Many new results approved for public talks - including three or four in this summary. • And now let’s embark on our Tour through Q2 ZEUS Report : 47. DESY PRC

  4. Kinematic Range of (x,Q2) Explored at HERA ZEUS Report : 47. DESY PRC

  5. Additional Variables in Photoproduction • Examples of LO processes LO direct x = 1 LO resolved x < 1 ZEUS Report : 47. DESY PRC

  6. Subjets in photoproduced jets Investigate structure of jets by looking for subjets. Quark and gluon jets are expected to be different due to different qg and gg couplings. ZEUS Report : 47. DESY PRC

  7. Subjet Multiplicity Subjet analysis senses differences in multiplicity and width of jets:  Njet quarks   Njet gluons ZEUS Report : 47. DESY PRC

  8. Subjet Multiplicity  Njet Ycut  as   Forward Jets more glue-like ZEUS Report : 47. DESY PRC

  9. (2nd jet) (3rd jet) (leading jet) Trijet Photoproduction • 3: scattering angle of th Leading Jet in the 3J CM. • Angular distributions reflective of reaction dynamics (quark/gluon) • In three jet events, the 3rd jet allows identification of fwd/back direction of leading jet in the 3J CM ZEUS Report : 47. DESY PRC

  10. Low-W photoproduction of Charm Differential cross sections Data lie above NLO calculations Events are tagged by hits in the “44m” tagger - 80 GeV < W < 120 GeV ZEUS Report : 47. DESY PRC

  11. From D* in DIS FINAL ZEUS Report : 47. DESY PRC

  12. F2C/ F2 Fraction of charm increases with decreasing x. Contribution of charm in DIS grows with x From D* in DIS ZEUS Report : 47. DESY PRC

  13. Measurement of s in dijet DIS Measure s from dijet cross section 2+1 and ratio: Select dijet events with : Region of small experimental and theoretical uncertainties Compare measured dijet ratio to NLO calculations (DISENT) ZEUS Report : 47. DESY PRC

  14. Study of High (x,Q2) e-p NC DIS First 8.6 pb-1 of 1998/99 First 5.1 pb-1 of 1998 data Searches For New Physics in e-p Search for Isolated High Pt Muons or Electrons in e-p One Candidate in First 5.1 pb-1 of e-p data before lepton cut Exp Bkg = 0.50 after Lepton ID 0.24 0.14 e 0.24 0.03  Data in Good Agreement w/ SM ZEUS Report : 47. DESY PRC

  15. High Q2 Neutral Current DIS ZEUS Report : 47. DESY PRC

  16. High Q2 Neutral Current DIS Direct Sensitivity to Z0-boson exchange ZEUS Report : 47. DESY PRC

  17. High Q2 Charged Current DIS Comparison of e+p to e- p at high Q2 ZEUS Report : 47. DESY PRC

  18. High Q2 Charged Current DIS ZEUS Report : 47. DESY PRC

  19. Charged Current & high-x quarks • Differences due to quark density and helicity • Potentially, direct extraction of d:u quark ratio and estimates of high Q2 sea quark distributions…. And… And… And… • Polarization (w/Lumi) will help …. Bring on the Lumi Upgrade ZEUS Report : 47. DESY PRC

  20. Looking Ahead to High Luminosity ZEUS Report : 47. DESY PRC

  21. Barrel Presampler: Energy corrections for hadrons and electrons over full detector, with minimal use of MC BPRE useful for 0/ separation Forward Neutron Tracker Scintillator fingers at 10 inside FNC for precise reconstruction of impact point. Improved Pt resolution for t-dependent studies Subcomponents newly operational in 1999 BPREsampler Forward Neutron Tracker  e- ZEUS Report : 47. DESY PRC

  22. StrawTube Tracker (STT) • Beam-tests at DESY of prototype sector and prototype electronics: • Multiplexing Scheme for digital readout designed, final prototype being produced • STT Short sectorproduction to begin next month, Long sector design complete. • Beamtest of STT, end-to-end, in September ZEUS Report : 47. DESY PRC

  23. Microvertex Detector (MVD) FMVD first prototype, ready for test beam Bonding machine at DESY • Barrel MVD Si acceptance tests, Forward MVD Si prototyping • Cabling and Interconnects - orders soon • Bonding and module production underway at DESY (Halle 1) now. • Progress on readout and trigger… MVD will participate at the Second Level “Global Tracking” (CDT,STT,MVD) trigger. • Much progress on all aspects of project goals. ZEUS Report : 47. DESY PRC

  24. End of Talk / Start of Next Run ZEUS is enjoying a rich variety of Physics Investigations A quick tour through Q2 with peaks at precision measurements of s, growing program in heavy flavors, searches for Exotics and measurements of weak-effects in DIS, STILL leaves out the vast majority of an active and growing Physics environment. New results from ZEUS are coming all the time. ZEUS is ready to maximize collection of ep data before the Upgrade. Last chance for some detectors and some physics. Progress on Lumi-Upgrade : Both new Trackers are meeting goals to be ready. The existing trigger and R/O components are ready NOW. ZEUS Report : 47. DESY PRC

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