Tuesday 10th March 1999
                                              Ian Tomalin

                MINUTES OF THE 28TH BEW MEETING
               =================================


Agenda
------
  Ian Tomalin        : LEP BEW results presented at La Thuile
  Elsa Merle         : Expected Contact Term Limits
  Marie-Noelle Minard: KORALZ/PYTHIA/HERWIG diffferences.
  Discussions ...


Ian Tomalin : LEP BEW results presented at La Thuile
-----------------------------------------------------

   - No new results from TEVATRON on t -> c Z. Old ones published.
   - No new results on e* production from HERA. Old ones are
     better than ours for M(e*) > E_LEP.
   - BES (China) will measure sigma(qq)/sigma(mumu) at
     2 < E_cm < 5 GeV by the end of the year. Will reduce existing
     errors by factor 2. => Better alpha_QED(M_Z).
   - BABAR can also do this using radiative events.
   - Other LEP experiments had no new difermion production results
     at 189 GeV. (Presented those from Nov. LEPC).
   - Disagreement between Jadach and Bardin on size of higher 
     order ISR/FSR interference corrections at LEP2.

Elsa Merle : Expected Contact Term Limits
-----------------------------------------
  - Takes contact term program from web.
  - In input data files, replaces ALEPH measurements by SM predictions.
  - Smears SM predictions by errors using random numbers, taking
    into account correlated and uncorrelated ones.
  - For each set of random number smearing, obtains contact terms
    limits.
  - Does this 50 times, and averages the 50 results to get 
    expected limits.
  - For dilepton contact interactions, agree fairly well with 
    measured limits.

Marie-Noelle Minard: KORALZ/PYTHIA/HERWIG diffferences
-------------------------------------------------------
  Compared radiative photons in data with different generators:
    - KORALZ is good.
    - PYTHIA produces too many photons with large P_t to the beam axis.
    - HERWIG produces too few multiphoton events.

Discussions
------------
  1) Excited lepton analysis probably not ready for Moriond.
     Confusion with KORALZ nu-nubar cross section and with
     missing t-channel production of electron neutrinos.

  2) How should we average the LEP results ? Ian will write proposal.
     Comments:
       i) Correct all cross sections and asymmetries to common
          definition for all experiments before averaging. Will need
          to decide what this definition is.
      ii) Decide for which difermion channels, one gains by averaging
          the experiments.
     iii) Decide for which new physics limits, we want combined
          results. Explain why S-matrix fit is not wanted.