Minutes of the collaboration meeting June 28, 2000  -Richard Jones
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1) Status of the analysis

>From Scott's results we have seen the states that we are supposed to
in each of the n-gamma samples he assembled:
 * 2-gamma: besides the pi0 and eta we have a clear Ks.  The eta-prime
        is missing, probably because it is too big to fit into the LGD.
        If so, this would be one of the things to look for in the BGV
        once we get gamma reconstruction running there.
 * 3-gamma: we have a big bold omega in pi0,gamma and a rather shy phi
        in eta,gamma.  Scott coaxed him out of hiding using side-band
        subtraction around the eta.  He also used a kinematic fitter to
        the gamma,eta hypothesis.  No evidence yet for the phi in pi0,gamma.
 * 4-gamma: we have a nice f2(1270) signal in pi0,pi0 and the a0(980)
        pops out in eta,pi0.  The size of this a0 cross section can
        take the break away.  Is it comparable in magnitude to the phi?

These initial results are encouraging.  Looking at these spectra, we
can see immediately how important it is to understand our backgrounds.
Scott has produced a study showing how the background under the omega
in the 3-gamma sample can be reduced by cutting on the energy in the
BGV.  At the meeting I (Richard) showed how the CPV can be used to estimate
the contamination from charged-particle events in a sample without
throwing away acceptance from random vetos.  At the July 20 meeting I
will show further results obtained from this method of using the CPV
in our analysis.

2) Progress in calibration

Last meeting Craig explained how he has set it up for individuals
working on calibration can enter their results into the central database.
He has entered the pedestals on an ongoing basis, and we now have the
official set of LGD gain constants in the map.  Several in the group are
now working on the timing calibration, and showed the status of their
work.  Russel's work on the tagger timing offsets is quite well advanced,
and he was able to show timing corrections as they track over a period
of runs.  Most of the time they were fairly stable, with jumps at points
where the cabling or timing of the stop was changed.  There were,
however, some anomalies including a few channels that danced around a
bit and tagger channels 17-19 that appeared to be missing left-right
coincidences.  We look forward to hearing from Russel at the meeting
what progress he has made in understanding these effects.

Cathleen has been doing the timing of the BGV channels.  She will show
the results she has obtained at the meeting.  Eric Koskinen will report
on his work in mapping out the dead cells in the LGD.  Erin Collins
will show results from the trigger studies she has been doing.

3) Plans to complete the makehits package and a wish list for new analysis
tools

At the meeting we identified several new tools that will be required
to take the analysis beyond its present stage.

 * a cluster cleanup tool
 * a proton finder
 * a kinematic fitter
 * an event summary record

The LGD cluster finder that we use today does not know about all of the
cuts that are made afterwards.  These cuts can sometimes exclude a part
of the deposited energy in cluster fragments that might better be re-
merged with nearby larger clusters.  This situation was discussed at the
meeting, and an analysis step for "cluster cleanup" was identified
as important.