[Sane-analysis] Minutes of April 28 Meeting

[Narbe Kalantarians]

_*Oscar:*_ Looking at Q2, nu, and W distributions for parallel data. Was 
getting some values of W2<0 and asking if this could be due to a problem 
with obtaining Q2 in the physics ntuple.  Also noticed that about ~10% 
of nu came out as 0. The negative W2  values seem to be from rescattering.

Hovhannes mentioned that he had adjusted the cuts in the Replay and is 
about to update the CVS version with them. The naught nu values were 
from events not passing the necessary cuts, but are being kept in so 
that quantities such as angle and energy can be recovered.

http://www.jlab.org/~rondon/sane/analysis/replay/?M=D


_*Hovhannes:*_ Extracted polynomial coefficients for no field data. 
Improved the pi0 calibration to where it has a resolution of better than 
7-9% depending on how background is fit.

Gave intermediate calibration constants to Anusha. Elastic peak seems to 
have a shift of ~400MeV. Also, Anusha's Replay seems to have a secondary 
peak in y (don't recall which specific variable this is);  one at 0cm 
and one at 50cm. Hovhannes asked if it could be from either the sieve 
slit correction or the momentum reconstruction from HMS. Mark mentioned 
that the HMS P reconstruction is well known and that he and Anusha would 
look further into this.


_*James:*_ Looking at particle tracking and constraining to the front 
tracker.  Looked at  the x and y values  for the tracker, lucite, and 
clusters. Saw that about 90% of cases for 2 lucite bars being hit the 
bars were adjacent to each other, which seems to make sense. The 
tracker-y seems to be approximately half as efficient, which also seems 
reasonable. Will look with updated Replay when it's checked into CVS and 
use track fitting routine that is in Replay for higher energies, where 
it should have mostly electrons with minimal bending. 

https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Particle_Tracking_to_Front_Tracker%2C_Target


_*Jon:*_ Looking at events with 2 clusters and 1 Cerenkov mirror hit.  
Sees narrow separation between clusters in x (~3cm) and wider in y 
(~10cm), but still not far away from the clusters overlapping. Will try 
fixing energy of one cluster while cutting on the other's to see if it's 
possible to see e-e+ pairs.

Looked at Cerenkov ADC spectrum for cases of 1 and 2 clusters. For the 2 
cluster spectrum there appears to be evidence of a 2nd photon peak. Will 
try subtracting (normalized) spectrum of 1 cluster from 2 cluster 
spectrum to pick out secondary peak.

https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Jrm_double_clust


_*Whit:*_ Looking at various algorithms that could be used for 
clustering for the neural network.
http://quarks.temple.edu/~whit/code/InSANE++/html/group__Clustering.html


As always, please let me know if I missed something  or got it wrong.


Next meeting will be May 5th at 3:30 pm.
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