Aidan Kelleher
Oct. 8, 2008


Last Week:

1) Re-ran analysis code on newly re-analyzed runs.
   a) required new ND to BB time shift (difference of about 4ns)
2) New code included background variables.
3) Looked at empty reference cell runs.  There were 4 empty reference cell 
runs for kin 4 (runs 4419-4422).  They ran for about 1 hour total, with an 
average T3 rate of about 45 Hz.  Chaining all the runs together, and 
applying the same cuts (coincidence, missing parallel momentum, q_perp, 
invariant mass) I get:

Cuts			Neutral Charged  Ratio	 1/sqrt(N)
All	      		24      67       0.358	 0.105
No W	 	     	39      144      0.271	 0.074
No W, No q_perp   	188     340      0.552	 0.044

4) Looked at my Monte Carlo with different resolutions for charged or 
uncharged particles.  Table is in the folder (table.pdf)


Meanwhile, using Seamus's method of background:

Summary of Asymmetry
Total number of neutral events: 95720
Total neutral events -- background subtracted: 88938
Total number of neutral events, helicity +: 47746
Total number of neutral events, helicity -: 47974
Raw Asymmetry : -0.0534893
Background Subracted Asymmetry: -0.0572983 +/- 0.00343446 (sub) 
	   +/-0.00334767 (stat) (5.84252% ) 
Number of Runs analyzed: 132
Nitrogen dilution factor: 0.943 <-- Seamsus's Thesis
Target polarization: 0.48
Neutron polarization: 0.86
Beam polarization: 0.835 <-- Seamus's Thesis
Proton leakage factor: 0.834 <-- Seamus's Thesis
A_phys = -0.245776

Still not sure about how error of subtraction is calculated.


To Do:
1) Rate dependence
2) Nitrogen Dilution
3) Find momentum distribution for nitrogen
4) Kin 2a target polarization into database