Tuesday 6th April 1999
                                              Ian Tomalin

                MINUTES OF THE 29TH BEW MEETING
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Agenda
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  Corinne Goy: Progress report on improving R_b measurement.


Corinne Goy: Progress report on improving R_b measurement
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Various studies made of QIPBTAG tagging efficiency -

  Using double tag technique at Z0 peak, and taking udsc efficiency
and hemisphere-hemisphere correlation from MC, b tagging efficiency
in data is slighty higher than in MC.

  Using semileptonic WW events, udsc tagging efficiency is higher
in data than MC.

  Correction for each of these pushes R_b at 189 GeV downwards.

  Efficiency of QIPBTAG to select tracks seems lower in data than
MC. Correcting for this by deleting tracks will push R_b upwards.
Study not yet finished.

  Also intended to modify b charged decay multiplicity.