1. Chris Crawford Blast Analysis Meeting 2004/09/24
H(e,e’p) Analysis
Chris Crawford
Blast Analysis Meeting
2004/09/24

2. Outline elastic cuts background comparison of yields
Helastic
based on Dec out-bending
Hcbc – wire chambers
for April in-bending data
Hpt – TOF elastic
new timing offsets for Feb,April data
background
comparison of yields
TOF only, WC
AL,R, m GE/GM , PbPt
projected errors

3. Hcbc – Wire Chambers [p,q,f,z]e, [p,q,f,z]p ) q,f,z (5 extras)
pe:qe pp:qp qe:qp fe:fp ze:zp pmiss
need better resolution (current re-crunch)

4. Timing Offsets flasher unstable for April runs retiming method
refit flasher peaks
aligned elastic timing peak in sets of 5k events
overall relative offsets from cosmics
use WC f to extract position offsets, slope

5. secondary peak

6. Hpt TOF elastic cuts cut on 48 TOF paddle combinations/side
fit (ptr+ptl):(ttr-ttl) to 2-d gaussian
elliptical cuts with parameter ns

7. Background Comparison
# events/C
Helastic
Hcbc
Hpt
2.4
3.2
5.5
7.6
7.7
7.9
2.2
2.9
4.8
7.1
6.9
7.5
3.8
5.0
1.4
.49
.20
.08
4.1
.21
.10
.46
.47
.54
.53
1.3
.30
.56
.59
.62
.73
1.5
2.7
.81
.26
.11
.03
1.6
2.3
.25
.08
.32
.29
.36
.52
.68
.65
.39
.35
.44
.62
.96
3.1
4.0
1.1
.36
.15
.07
2.9
3.3
1.0
.37
.16
.08

8. Yields Comparison TOF cuts only (lr ntuple)
MC includes WC acceptance (see forward paddles)

9. Fit Method Super-ratio Method 2 equations in P, R
i = left,right
j = Q2 bin (1..n)
b = spin angle
Fit Method
Super-ratio Method
2 equations in P, R
for fixed bin j
independent polarization in each bin!
2n parameters Pj, Rj
Global Fit Method
fit ALj, ARj to above formalism with P, Rj
n+1 parameters
n+2 (+spin angle?)
same advantage as super-ratio method
PbPt still cancels

10. Outbending Data (Dec)

11. Inbending Data(Feb, Apr)

12. Combined Datasets with Projected Errors
based on additional 325kC of data
32% increase in density
3.2£ reduction in errors compared with 50kC in April