[Sane-analysis] Minutes 0f Sept 8 2010 Analysis Meeting

[Narbe Kalantarians]

_*Hoyoung:*_ (From Sept 7) Has done the packing fractions. Going through 
and investigating those that are low values (~40% or so). Some of the 
PF's seem to be really different, for different settings, claiming to be 
of the same load. Oscar is going to check with James and Jon once 
Hoyoung gives the run numbers.
Will transpose the results to table format with the errors.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Packing_Fractions_Tables


_*Hovhannes:*_ Looking at slow raster distribution for perpendicular 
runs 72487-72550. Focusing on region where there are holes; taking a 
slice of +-2mm around the center. Sees higher counts on one side of SRx 
(with +- 2mm for SRy) compared to the other. Plus the distribution looks 
trapezoidal. For the This could be an acceptance effect, dependent on 
the angle. The SRy distribution (with +- 2mm for SRx) looks more 
symmetric with peaks and troughs on the top probably from the SR. These 
are fairly fine (few cm's) and won't really affect things too much for 
BigCal, with a resolution of ~0.5cm.
Started looking at perpendicular asymmetry, correcting for beam and 
target polarization and live-time. The asymmetries are small  but 
stable. With a typical dilution factor of ~15% these will be reasonable.


_*Narbe:*_ Following up on pi0 mass study(Aug 18), looking at its 
dependence on energy. Using the GEANT, throwing pi0s from target and 
smearing on reconstructed energy 9%, as seen in data. Initial resolution 
of GEANT is significantly finer than data because GEANT doesn't take 
into account the fact that the lead blocks are radiation-damaged. Looked 
at pi0 mass in bins of reconstructed energy (250MeV wide). The centroid 
of the peak seems to shift more to higher values at higher energies. 
This is also seen in the data.
Will move back on to the dilution factor effort and start working on 
systematics for the kinematic variables.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/SANE_GEANT#09.2F08.2F2010


_*Jon:*_ Did some work on the energy reconstruction to cross-check 
calibrations, using earlier elastics data. Planning on moving onto 
something else.


_*Anusha:*_ After doing the slow raster calibrations for offsets, sees 
that the elastic delta peaks have shifted more than before. Looked at 
both early elastics data without field (left side panels on link) and 
compared with polarized elastic data (right side panels on link). Both 
show the extra shifting. Looking further into this with Mark.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Magnetic_Field_ON/OFF_correlations


_*James:*_ (Posted last week) Looking at parallel asymmetries, noticed a 
few runs (72945-72947) with half-wave plated status being opposite of 
what the asymmetry should be. Did some investigating and found that MCC 
had some ROC's crash around that time and were rebooted, possibly back 
into their default state(s). It is also possible that these are not 
synced with the EPICs. Made a table for the helicity scalers per run.
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Raw_Asymmetries#Charge_Normalized_Asymmetry:_8.2F25.2F2010
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Dead_Time#Table_of_Scalers_per_Run:_8.2F25.2F2010


As always, please let me know if I missed something or if I made a mistake.

Next meeting will be Sept 15.
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