minutes of GEn01 meeting (May 14, 2003) - revised

From: Glen Warren (gwarren_at_anti-spam)
Date: 15-May-2003 10:23:46


GEn01 analysis meeting May 14, 2003
====================================

attended by: Paul, Oscar at UVa
               Donal, Hongguo, Frank, Nikolai and Glen at JLab

*** Revised version adds comments on hszbeam and gave Frank a
*** new task.

REPORTS

*) GMn: Glen has looked received the values of Gmn/dipole from Jim Kelly
from his fit (PRC 66 065203 (2002)) and compared them to the Basel fit.
   He concluded that the best approach was to take the number from Jim
Kelly, but increase the error to include the Basel fit.  The resulting
numbers are Gmn/mu/Dipole = 1.018+-0.011 and 1.054+-0.018 for Q2=0.5 and
1.0 respectively.

This still leaves the issue of how this impacts Gen.  We agreed to ask
Arenhoevel for GMn=1.054*mu*Dipole and Gen=1.1*Galster.

*) Background: no progress

*) 98 data: no further comments on analysis.  Frank suggested that we
look at the 98 data for the long paper.  We should also look over the
field setting codes for 98 and 01 to see if there should be momentum
offsets applied to both.

*) paper: no progress

*) MC work: need to study pion production contributions at Q2=1

*) packing fraction: Nikolai raised the issue of recalculating the
packing fraction with the momentum shift, 2) how are we going to handle
the rotated stick.  Nikolai first guess is that the p.f. will change by
1-2% with the shifted momentum.  He can do this be rescaling the
momentum in the ntuple, so it should be fairly straight forward.

Nikolai also recalled that there was clear evidence that the material in
stick 4 had settled.  Looking at the pictures of when the stick was
pulled, it was clear.  Nikolai was asked to represent the evidence for
settling.

*) stick 3:  Nikolai asked how are we going to handle the rotated stick.
Nikolai will also review Glen's comments on the dilution factor for
stick 3 and make further suggestions.  One possibility was to look at
proton asymmetries for the left and right side of the cell.

*) Pass 4: We agree to remove the 0.33% offset, leave the ndet where it
is passed on Glen's examination of the ratio of peak heights which
suggested an angle change of only +0.1 degrees.  Frank will start the
4th pass immediately.  Note that not moving the ndet appears to conflict
with ypos comparison of data and MC.

*) hszbeam: Glen questions the wisdom of the hszbeam cut.  In the past, 
it was argued that there was clean separation of the cell and 4K shield 
for Q2=1, thus allowing a 4K shield cut.  Glen doesn't see a clean 
separation in the cut data.  Frank says that the separation existed in 
the uncut data.

TO DO

Donal
    *) Ask Arenhoevel for GMn=1.054*Dipole, GEn=1.1*Galster table
    *) work on paper

Glen
    *) look at 98 and 01 field setting codes

Nikolai
    *) Redo packing fraction with shifted momentum
    *) Review Glen's comments on the ratio of d.f. for stick 3 and 4 and
make suggestions are further course of action.
    *) Resubmit evidence for settling in stick 4.
    *) Look at proton asymmetry for left and right half of stick 3 as a
means to study differences in d.f. for stick 3 and stick 4.

Frank
    *) Start fourth pass
    *) accidentals
    *) Resubmit evidence for separation of 4K shield and cell.

Hongguo
    *) Radiative corrections
    *) Target field angle uncertainties
    *) kinematic uncertainties

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