ZEUS Physics Overview

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ZEUS Physics Overview
R. Yoshida Argonne National
Laboratory ZEUS spokesman
DOE visit, 11 March 2004

• A sampling of recent physics results
• Charged current cross-section
• Charm production in DIS
• Exotic hadrons (glueballs and pentaquarks)
• Contact interactions, extra-dimensions limits
• HERA implications for the LHC an example case
• HERA-LHC workshop
• Current status and conclusion

Please see also my HEPAP talk http//doe-hep.hep.
net/HEPAPYoshidaNov2002.pdf
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Pace of paper production has not slacked offif
anything increased in the recent years.
Papers with 100 citations (spires)
ZEUS papers are consistently among the most cited
papers.
A sampling of recent papers ?
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Argonne analysis
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Argonne analysis
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Exotic baryons at ZEUS
Pentaquark candidate
Glueball candidate
Argonne analysis
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Contact interactions, extra-dimensions limits
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Implications of HERA for the LHC

• Parton distributions ? relevant to all processed
  at LHC
• Diffraction ? HERA measurements may make
  quantitative prediction. Important as background
  for many processes, and also as signal
  (diffractive Higgs)
• Underlying event, fragmentation ? HERA ep
  environment allows for precise measurement of
  non-perturbative effects. Important to assess
  background.
• Hard cross-sections ? precise jet cross-sections,
  heavy quark cross-sections. Important ingredient
  in sorting out new physics at the LHC
• Many other issues One example ?

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• Precise jet measurements are being made at ZEUS
• 1 energy scale
• NLO QCD under good control

An example impact of ZEUS data on LHC physics
DIS jets
Precise measurement of as
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Photoproduction of jets
Jets can probe the gluon
Because measurement and theory are under
control?gives meaningful information in QCD
analysis of proton PDF
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Inclusive DIS measurements scaling violation
gives access to gluon densities
Including the jet data (using quantitative
uncertainties) in the QCD fit of parton densities

xg
Very Preliminary
Very Preliminary
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Just as at the Tevatron, high Et jets at the LHC
is one of the most important windows to new
physics. Almost a decade ago, Tevatron high Et
jets seemed to indicate some new physics.
PDF uncertainties, unquantified
Difficult systematics of jet measurement
Note ZEUS jet uncertainties are a few
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Extra-dimension study for ATLAS
Medium to high-x gluon distributions, Jet
uncertainties -- important in extending physics
reach.
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• Organized by HERA/DESY and LHC/CERN, and
  sponsored by the labs.
• The main workshop for LHC in 2004
• 1-year long. Aim for quantitative studies.
• http//www.desy.de/heralhc

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Goals of the workshop

• To identify and prioritize those measurements to
  be made at HERA which have an impact on the
  physics reach of the LHC.
• To encourage and stimulate transfer of knowledge
  between the HERA and LHC communities and
  establish an ongoing interaction.
• To encourage and stimulate theory and
  phenomenological efforts related to the above
  goals.
• To examine and improve theoretical and
  experimental tools related to the above goals.
• To increase the quantitative understanding of the
  implication of HERA measurements on LHC physics.

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HERA has began to deliver luminosities
approaching the required rate
Goal .7-1 fb-1 in 1000 days
? Luminosity progress
1 fb-1 in 1000 days
goal till summer04
Rate of lumi accumulation?
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The ZEUS detector is working well.
New MVD and STT?
Working well

• Neutral Current DIS

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Conclusions

• ZEUS is in the process of producing numerous
  important results from HERA I spanning topics
  ranging from pentaquarks to extra-dimensions.
• The importance of HERA results to LHC is
  recognized by physicists at LHC and at
  HERA?strong support from CERN and DESY on the
  HERA-LHC workshop.
• HERA is the only HEP collider in Europe until the
  LHC turn on. HERA is a source of young
  physicists with strong experiences in high-rate
  hadron-collider experimentation and QCD.
• HERA and ZEUS are about to enter its most
  productive stage. Five fold increase in
  luminosity, new detectors (MVD, STT) and lepton
  beam polarization.
• The next 3.5 years (end of HERA II mid-2007) is
  the culmination of an enormous efforts by all of
  the international members of the ZEUS
  collaboration.