[Sane-analysis] Minutes of December 22 Analysis Meeting

[Narbe Kalantarians]

_*Hoyoung (Dec 21):*_  Looking into runs which gave unexplainable 
different packing fractions from same target material load; 72828 and 
72957. Checked slow raster (x and y) distributions for these and they 
looked similar. So this didn't provide any smoking gun.
http://www.jlab.org/~hykang/pf/recent/
Preparing radiative corrections code provided by Karl Slifer (used for 
RSS) to use with HMS data. Will input latest CLAS fit results from 
Sebastian into this.
Will provide some slides to James giving updates on the 
packing-fractions/dilution-factors and (parallel) HMS asymmetries for 
the Hall C meeting in January.


_*James*_: Looked at physics and measured asymmetries using kinematic 
bin tables generated by Narbe. For physics asymmetries added corrections 
for charge normalization, livetime, polarizations, and toy dilution 
factor that uses 2 measured packing fractions as input. The asymmetries 
look reasonable but the higher <Q^2> bin (5[GeV^2]) seems to have very 
low statistics.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Binned_Asymmetries#Physics_Asymmetries.2C_Para_and_Perp:_12.2F22.2F2010 
Posted draft of talk for Hall C meeting.
http://twist.phys.virginia.edu/~jdm2z/sane/hallcwinter2011/HallCWinter2011.pdf


_*Anusha:*_ Obtained preliminary packing-fraction/dilution from NH3 
data. Used a 4th order polynormial fit region  in W surrounding elastic 
peak (0.7< W <1.1[GeV]) on the MC, which is composed of only He and N, 
to get the background. Subtracted the P4 fit function from the NH3 Data 
(Data-MC) to get the ratio with the NH3 Data ((Data-MC)/Data). Minimizes 
background dilution by using a scale factor (dat/MC for 0.8<W<0.9[GeV]). 
Got a scaling factor of 1.3, which is high, but got background dilution 
to about 0. This might be fro mthe data being spread more in lower W 
than the MC.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/MC_with_NH3
Working on xptar vs W correlation with azimuthal correction similar to 
RSS. Will try broadening MC peak by transporting B-field to forward region.


_*Jon:*_ Looked some more at Cerenkov timing.  Looked at TDC peaks, 
binned based on the sum64 row and column that was triggered for that 
event. The peaks for each row and column were then fit for each run. 
Hovhannes mentioned that the replay code has been updated considerably 
since then and some of the cuts used might be obsolete because of new 
corrections in the replay. The whole procedure is well detailed on his 
wiki page post.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/JrmCerTiming


_*Luwani:*_ Found the bug in his code for the energy distributions that 
was causing the multiple counting for photons and (effectively) neutral 
pions.


_*Narbe:*_ Per the effort to understand what B-field direction to use 
for the analysis, looked at HMS data for runs where this discrepancy was 
first seen (perp data). Rechecked some Carbon runs around this period 
and looked at distributions, comparing data and MC (black and red 
curves, respectively). Run 72436 looks the worst (probably bad chambers) 
and then 72505. The data plots for xptar vs yptar show a smaller region 
than what is seen with the MC. Anusha will make similar plots.
http://twist.phys.virginia.edu/~narbe/SANE/analysis/CCHe/?C=M;O=D
Asked Hoyoung to see how packing fractions might be affected for 5.9GeV 
(parallel) data by decreasing size of slow raster for the data (~0.8cm 
radius). The slow raster around that time was larger; 1.4cm radius, 
compared to 1.0cm radius.
Looked some more at cluster position distributions with GEANT-MC. Tried 
not using threshold energy cuts for the BigCal blocks. The gap seem in 
the region where the blocks are supposed to change is still there. Found 
that it's from the reconstructed energy (possibly) not registering for 
that region. Still looking into it.
http://twist.phys.virginia.edu/~narbe/SANE/analysis/GEANT/acceptance/v5/5.25/?C=M;O=D


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

Next meeting will be January 5, 2011, where we will do practice runs for 
the students' talks for the Hall C meeting.







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