minutes of GEn01 meeting (May 14, 2003)

From: Glen Warren (gwarren_at_anti-spam)
Date: 15-May-2003 10:16:48


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

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


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.


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

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

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