Difference between revisions of "Final analysis"
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| + | =Polarimetry= | ||
| + | |||
| + | Compton | ||
| + | |||
| + | 87.41 +/- 0.12 (stat) +/- 1.77 (sys) % | ||
| + | |||
| + | Moller | ||
| + | |||
| + | 88.92 +/- 0.04 (stat) +/- 1.12 (sys) % | ||
| + | |||
=Compton= | =Compton= | ||
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http://ace.phys.virginia.edu:8080/HAPPEX/2582 | http://ace.phys.virginia.edu:8080/HAPPEX/2582 | ||
| − | Final result: 87.41 +/- 0.12 (stat) +/- 1. | + | Final result: 87.41 +/- 0.12 (stat) +/- 1.77 (sys) % (??) |
chi^2/NDoF = 1.09 for 13 points over the experiment | chi^2/NDoF = 1.09 for 13 points over the experiment | ||
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|- | |- | ||
! | ! | ||
| − | ! Uncer. (%) | + | ! Rel Uncer. (%) |
! | ! | ||
|- | |- | ||
| Line 34: | Line 44: | ||
|- | |- | ||
| Analyzing Power | | Analyzing Power | ||
| − | | | + | | 1.53 |
| | | | ||
| + | |- | ||
| + | | TOTAL | ||
| + | | 2.03 | ||
|} | |} | ||
| Line 67: | Line 80: | ||
w/ the radiative correction: | w/ the radiative correction: | ||
analyzing power = 0.018299996 +- 0.00002583 (sta.) +- 0.000279099 (sys.) | analyzing power = 0.018299996 +- 0.00002583 (sta.) +- 0.000279099 (sys.) | ||
| + | |||
| + | |||
| + | =Moller= | ||
| + | |||
| + | http://www.jlab.org/~moller/e02-006.html | ||
| + | |||
| + | Final result weighted average: 88.92 +/- 0.04 (stat) +/- 1.12 (sys) % | ||
| + | |||
| + | (not sure if the systematic is relative or absolute) | ||
| + | |||
| + | ==Systematic Error== | ||
| + | |||
| + | Sasha's report at the Jan 2011 collaboration meeting | ||
| + | http://www.jlab.org/~moller/docs/PREX_Col_01_29_2011.pdf | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! | ||
| + | ! Uncer. (%) | ||
| + | |- | ||
| + | | Fe Pol. | ||
| + | | 0.25 | ||
| + | |- | ||
| + | | Targ Discrep. | ||
| + | | 0.5 | ||
| + | |- | ||
| + | | Targ Saturation | ||
| + | | 0.3 | ||
| + | |- | ||
| + | | Analyzing power | ||
| + | | 0.3 | ||
| + | |- | ||
| + | | Levchuk | ||
| + | | 0.5 | ||
| + | |- | ||
| + | | Targ temp | ||
| + | | 0.02 | ||
| + | |- | ||
| + | | Dead time | ||
| + | | 0.3 | ||
| + | |- | ||
| + | | Background | ||
| + | | 0.3 | ||
| + | |- | ||
| + | | Others | ||
| + | | 0.5 | ||
| + | |- | ||
| + | | Current diff | ||
| + | | 0.3 | ||
| + | |- | ||
| + | | TOTAL | ||
| + | | 1.12 | ||
| + | |} | ||
Revision as of 12:41, 12 April 2011
Polarimetry
Compton
87.41 +/- 0.12 (stat) +/- 1.77 (sys) %
Moller
88.92 +/- 0.04 (stat) +/- 1.12 (sys) %
Compton
Mindy's HAPLOG post:
http://ace.phys.virginia.edu:8080/HAPPEX/2582
Final result: 87.41 +/- 0.12 (stat) +/- 1.77 (sys) % (??)
chi^2/NDoF = 1.09 for 13 points over the experiment
Systematic Error
| Rel Uncer. (%) | ||
|---|---|---|
| Laser Pol. | 0.07 | http://ace.phys.virginia.edu:8080/HAPPEX/2530 |
| Gain shift | 1.3 | email from Megan Friend, see below |
| Collimator Pos. | 0.02 | http://ace.phys.virginia.edu:8080/HAPPEX/2568 |
| Nonlinearity | 0.3 | http://ace.phys.virginia.edu:8080/HAPPEX/2569 |
| Analyzing Power | 1.53 | |
| TOTAL | 2.03 |
Systematic Error Notes
- From Megan over gain shift:
I don't think I'm going to be able to get a number for the gain shift during PREX, although it should scale linearly with signal-background size. Using the 1% gain shift we saw during HAPPEX (signal+bkg to background = 122e6 to 53e6), that would give us a 0.8% gain shift for PREX (signal+bkg to background = 48e6 to 30e6 at 1kHz * 3.3 to convert to 30Hz). This would give us a change in the final polarization number of 1.3%, if it's folded into the background subtraction ( which comes from comparing a background subtraction of (48e6-30e6*(1.008))/(48e6-30e6) ). So I'd say the possible gain shift gives you a 1.3% systematic error.
- From Megan over radiative correction:
I just ran through the PREX data to add in a radiative correction, and I get that this increases the analyzing power by 0.3% (from 0.01828903 to 0.01834393). This is consistent with what I've seen, so I think it's safe to add that in there.
There is an increase in analyzing power of 0.3%, which corresponds to a decrease in beam polarization by 0.3%. Therefore, the final analyzing power should multiply by (1+0.003) due to A_real = A_exp * (1+0.3%)
w/o the radiative correction:
analyzing power = 0.01824526 +- 0.00002583 (sta.) +- 0.000279099 (sys.)
w/ the radiative correction:
analyzing power = 0.018299996 +- 0.00002583 (sta.) +- 0.000279099 (sys.)
Moller
http://www.jlab.org/~moller/e02-006.html
Final result weighted average: 88.92 +/- 0.04 (stat) +/- 1.12 (sys) %
(not sure if the systematic is relative or absolute)
Systematic Error
Sasha's report at the Jan 2011 collaboration meeting http://www.jlab.org/~moller/docs/PREX_Col_01_29_2011.pdf
| Uncer. (%) | |
|---|---|
| Fe Pol. | 0.25 |
| Targ Discrep. | 0.5 |
| Targ Saturation | 0.3 |
| Analyzing power | 0.3 |
| Levchuk | 0.5 |
| Targ temp | 0.02 |
| Dead time | 0.3 |
| Background | 0.3 |
| Others | 0.5 |
| Current diff | 0.3 |
| TOTAL | 1.12 |
