[Sane-analysis] Minutes of Feb 8 Analysis Meeting

[Narbe Kalantarians]

_*Jon:*_ Applying an earlier model of the e+e- background correction, 
resolves the discrepancy/gap seen in the 2 beam energies for A_1(x), as 
well as the W-dependence in the para and per asymmetries.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/JrmA1PairBGCorrection
Will try with more recent and more sophisticated model, which has the 
position dependence seen in Hovhannes' study.


_*Whit:*_ Did an efficiency study for the Cerenkov. Looked at energy 
dependence and at each individual mirror. Uses an energy cut E' > 0.8 
GeV; will try higher cuts. The Cerenkov efficiencies seem fairly 
uniform, with the bottom mirrors losing efficiency at higher energies.
http://quarks.temple.edu/~whit/SANE/sane_meetings/2_8_2012/


_*Narbe:*_ After correcting GEANT to randomly seed events/iterations and 
correctly accounting for aluminum (windows, nose, and tail pieces), the 
df's are smoothed out and seem to compare fairly well with his model 
calculations (F1F209) and is consistent with those done James and Jon, 
using SLAC_DIS.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Kinematics#02.2F08.2F2012
Will do a new iteration of df's for James to use once enough statistics 
are gathered.


_*Anusha:*_ Obtained and applied elastic dilution factors for the 
elastic, single-arm asymmetries, as well as the proton form-factor ratio 
GEp/GMp. The ratio doesn't change significantly, but the error improves 
some.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Dilution_Factor_from_NH3#Updates_on_02.2F08.2F2012_.28Used_df.27s_for_Top_and_Bottom_target_seperately.29
Applied aluminum to the Carbon target in the MC. This shows a 
contribution of ~7%, which seems reasonable, given that aluminum would 
factor more for C than for NH3.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Updates_on_02/08/2012-C_with_Al_added


_*Hoyoung(Feb 9):*_ Trying to finish last details for packing fractions. 
Some of the C/C+He runs give a large discrepancy for data/MC ~0.87, 
which over-corrects corresponding packing fractions, making them 
unrealistic. Has repeatedly checked and doesn't seem to be making any 
mistakes of his. So the C_He might not be well understood in the MC. 
These are the earlier 4.7GeV perp runs. Other than that, the 5.9GeV 
perp, and latter 4.7 perp packing fractions seem reasonable, along with 
those for parallel.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Packing_Fraction_using_pol_hms_single
Will try comparing the NH3 data for these to see if there is some 
discrepancy in the data. In the end, though, the decision may be made to 
use the more reasonable packing fractions from another setting that used 
the same loads and inserts.
Made progress in HMS asymmetries. Calculating error-bars, correcting for 
polarization, charge, and dilution factors.
https://hallcweb.jlab.org/experiments/sane/hykang/HMS_asym/20120209/
Will use same code for elastic radiative tail (MASCRAD) that James and 
Jon are using for their asymmetries.


***During the next 2 meetings, those with talks for the collaboration 
meeting will present their drafts.


As always, please let me know if I missed anything or if I made any 
mistake(s).


Next meeting will be Feb 15, 3:30 PM (JLab time)




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