Contents:

1. Convenors
2. Subgroups and Participants
3. Proposed topics
4. NEW: Proceedings
5. Calendar of the meetings
6. Transparencies of the meetings
7. Relevant literature
8. Other interesting information

Experimental convenors:
       
      Stefan Tapprogge (ATLAS),
        CERN 40-5c, 12
        tel: 0041-22-767 1256,  fax: 0041-22-767 8350
      Michael Dittmar (CMS),
        CERN 21-1, 29
        tel: 0041-22-767 3585, 

        To send mail to all convenors, click  here

The following list contains the participants who have signed up for the QCD working group.  

If you want to join the QCD working group, please send an e-mail to the covenors. You will be put on our mailing list. Furthermore you might want to check the list of subgroups which have been formed (see below) and if you want to contribute to one of the subgroups, please contact in addition the coordinator(s) of the subgroup(s).  

The list of subgroups indicates the topics which are going to be addressed during the workshop.

The list of study topics for the QCD Working Group is organized below in several different ways, so that a single topic of investigation may be found under more than one category.

This list is not etched in stone, but in silicon, and will be revised according to the input of the working group members before and at the first meeting on 21 January 1999.

In the case of QCD topics that are being investigated by the other working groups, our role is limited to providing benchmark production cross sections as needed and to investigating the links between these topics and the wider questions of QCD.

Processes

• Hard
  1. Jet production
  2. Single and double prompt photon production
  3. W and Z production; W and Z production with jets (in cooperation with the Electroweak Group)
  4. Top quark production (in cooperation with the Top Physics Group )
  5. Bottom quark production (in cooperation with the b-Production Group)
  6. Production of heavy quark bound states
  7. High P_T neutrino production
• Hard double parton scattering processes.
• Hard/less hard
  1. Internal structure of jets.
  2. P_T distribution in lepton or photon pair production and in W and Z production.
• Hard/Soft
  1. The structure of the underlying event in collisions with a hard scattering.
  2. Rapidity gaps in collisions with a hard scattering.
  3. Diffractive scattering of one of the incoming hadrons in collisions with a hard scattering.
• Soft
  1. The total cross section.
  2. The elastic cross section near the forward direction and other pomeron exchange studies.
  3. The structure of the final state in minimum bias events.

Parton distributions and parton-parton luminosities

• The currently available sets of parton distributions.
  1. What sets are available?
  2. How do they compare?
• How well do we know parton distributions?
  1. What assessments of errors are available?
  2. Where are the errors big and how can we get the needed information?
     • Flavor dependence (eg. up versus down at large x).
     • The gluon at large x
  3. How will the uncertainties in the parton distributions affect the interpretation of LHC data?
• What are the needs/prospects for determinations of the parton distributions in the years leading to the LHC start date?
  1. New data.
  2. Improvements in the analysis.
  3. Collaborations carrying out the work.
• How well could one determine the parton distributions from LHC data alone?
• How well could one determine proton-antiproton luminosity from a measurement of the W and Z production rates?

Monte Carlo event generators

Note: We anticipate that there will be a future study devoted entirely to the improvement/development of Monte Carlo event generators for the LHC. Here we hope merely to sketch the state of the art and to suggest avenues for future improvements.
• The currently available event generators.
  1. What event generators are available?
  2. How do they compare?
• How well do they work at 2 TeV and how well may we expect them to work at LHC energies?
  1. What hard processes are included and how accurately are they incorporated?
  2. How well is the radiation pattern associated with the hard scattering modeled?
  3. What uncertainties are there in the description of the underlying event in an collision with a hard scattering?
  4. What uncertainties are there in the description of the development of the final state?
  5. How well are minimum bias events modeled?
• What are the needs/prospects for determinations of the parton distributions in the years leading to the LHC start date?
  1. New data.
  2. Improvements in the analysis.
  3. Collaborations carrying out the work.

Higher order perturbative calculations

• The currently available calculations.
  1. What has been calculated?
  2. For calculations in the form of computer programs, where can one get the programs?
• Do we have the cross sections that we need at next-to-leading order?
• If cross sections are lacking, do we have the required matrix elements?
• What are the needs/prospects for calculations at (next-to)²-leading order?
• What are the needs/prospects for incorporating next-to-leading order calculations into event generator Monte Carlo programs?

  Soft gluon summations

  • Transverse momentum distributions.
  • Modifications of fixed order perturbation theory in the large x region.
  • BFKL summation for the small x region and for two hard scatterings at very different rapidities.

  Testing QCD

  • Examining the short distance matrix elements for quark-quark, quark-gluon, gluon-gluon scattering.
  • Testing whether the strong coupling is properly running and is the same as that measured in lower energy experiments.
  • Testing whether emission of many relatively soft gluons works according to QCD theory.
  • What tests of QCD could we perform using the internal structure of high P_T jets?
  • Where does current data disagree with QCD theory. Why?

  Experimental analysis of the final state

  • Algorithms for defining jets and jet cross sections.
  • Algorithms for defining "isolated photons."

  Experiments before the start of the LHC

  • What experimental information from, for example, the Fermilab Tevatron and HERA would help us to be better prepared for the start of the LHC?

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  Proceedings

  The write-up of this working group can be found as hep-ph/0005025 at Los Alamos.

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  Calendar of the meetings
  1st Meeting: Thursday January 21, TH Auditorium, CERN,  9am-6pm

  Goal of this first meeting was to review the present experimental and theoretical status on QCD issues, and to discuss the items for studies in the working group.

  
  The 2nd meeting is going to take place on Monday April 12. A preliminary version of the agenda can be found by following this link .

  The last meeting was on:

  • October 11th 1999, 9:00 - 17:00 Salle Dirac (40-SS-D01)
  The agenda for the next meeting can be found by following this link . As soon as electronic versions of the talks are available, a link will appear on the agenda.

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  Transparencies of the meetings
  The agenda of the 1st meeting which took place on Thursday January 21 can be found by following this link . All the transparencies have now been scanned and links to POSTSCRIPT and PDF files are available.

  Transparencies of the talks from the plenary meeting on May 25th and 26th:

  • D. Soper 'Jets and partons'
  • S. Tapprogge 'QCD studies at the LHC'
  • W.J. Stirling 'Parton distributions and their implications for LHC'
  • M. Dittmar 'Cross-section measurement at the LHC'
  The agenda of the third meeting contains links to electronic versions of the talks where available.

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  Relevant literature
  Best to be found now in hep-ph/0005025 at Los Alamos.

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  Other interesting information:
  • check out the Web page  of the Fermilab workshop on QCD and weak boson physics (Jan - Dec 1999)
  • check out the Web page of the Les Houches Workshop on LHC physics (June 7-18 1999)
• Information on parton densities from the Durham HEPDATA web page .

Accommodation

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