[Sane-analysis] Minutes of May 18 Analysis Meeting

[Narbe Kalantarians]

_*James:*_ Prepared an (updated)analysis run list.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Good_Runs_for_Analysis

Started looking at A_1 and A_2, working with Jon.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/A1%2C_A2_and_Structure_Functions#Update_to_A1.2C_A2

A_1 seems to be  twice the size it's supposed to be. This might be from 
the coefficients (code-wise). Will check calculations. Preparing tables 
to get F_1 and R (via F1F209) for the physics asymmetries.


_*Anusha:*_ Comparing data/MC for Carbon runs with and without Helium 
with B-field in both parallel and perpendicular. Applying slow-raster x 
and y offsets and using to calibrate beam positions offsets.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/C_runs_with_Parallel_Field_ON
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/C_runs_with_Perp._Field_ON

Will try applying azimuthal corrections to perpendicular data. The 
data/MC comparisons she's getting are inconsistent with those seen for 
the packing fractions, especially regarding the out of plane angle 
(xptar) for the perp data.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Packing_Fractions_Tables

Her, Hoyoung, and Narbe coordinate a systematic comparison  to find 
where this is coming from.


_*Whit:*_ Doing a study of the efficiency and (pion) rejection) of the 
detectors.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Whit#Efficiency_and_Rejection
For the plots; black curves are for pions, red curves for leptons.

There might be a bug in the code, causing a double/triple counting.

Has GEANT4 MC set up to compile on batch farm. Will work on getting 
database connection setup.


_*Hoyoung (05/19/11):*_ Working on getting system dead-time. Calculating 
coefficients for scaler, which are consistent with what Oscar gets for 
the unpolarized runs. Applied this to some NH3 runs. This is using the 
2second timing. Will try using the (cumulative) numbers for entire runs 
and look at parallel data, which has the data asymmetry dominating. 
Wrote a model for system dead-time, which gives the probability for a 
(200us) dead-time.
http://www.jlab.org/~hykang/deadtime/20110519/

Mark and Oscar suggested looking into what is done for dead-time 
corrections in parity violation experiments.


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

Next meeting will be May 25th 3:30pm JLab time.


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