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simpler to check DSA, which we start with Using same method for both team ◦ Divide phi_h – phi_S to 100 angular bins ◦ For each bin, calculate raw asymmetry A raw = (N + - N - )/ (N + + N - ) ◦ Then fit the DSA modulation We found ◦ The difference remains ◦ Each team’s result is consistent with its own previous one Therefore ◦ Good News: each team is self consistent, not likely a coding error ◦ Difference from low level of the analysis Transversity Analysis Meeting Jin Huang 3
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Final Story on Cross Check between Red Team and Blue
Team ResultsJin Huang, Xin Qian
For Transversity Analysis MeetingMay 3, 2010
Jin Huang <[email protected]> 2Transversity Analysis Meeting
From Last Meeting: Difference remains w/ run cut sync After run list/cuts/variable adjustment
◦ DSA Asymmetry is very consistent◦ Angular modulation became more consistent (not totally)◦ The remaining difference is investigated during last week
Jin Huang <[email protected]> 3
simpler to check DSA, which we start with Using same method for both team
◦ Divide phi_h – phi_S to 100 angular bins◦ For each bin, calculate raw asymmetry
Araw = (N+ - N-)/ (N+ + N-)◦ Then fit the DSA modulation
We found◦ The difference remains◦ Each team’s result is consistent with its own previous one
Therefore◦ Good News: each team is self consistent, not likely a
coding error◦ Difference from low level of the analysis
Transversity Analysis Meeting
We tried … and found …
Jin Huang <[email protected]> 4
The phi_S, theta_S data had problem
Transversity Analysis Meeting
Further check we found
Jin Huang <[email protected]> 5
Both team are using their own copy of root files developed from original skim ones.
We found there is a problem on phi_S -> phi_S + pi affecting all transverse root files last October
A fix is applied blue team files in December◦ It was correct
Another patch was generated for my copy of root files in January◦ However, ~10% of run was not corrected in the
patch
Transversity Analysis Meeting
History of the problem
Jin Huang <[email protected]> 6
Xin generated an updated patch for my copy of data Multiple Check event by event Confident no further problem on spin angles
Transversity Analysis Meeting
What now?
Jin Huang <[email protected]> 7
A_LT modulation with polarization correction
Transversity Analysis Meeting
DSA agree well now
Jin Huang <[email protected]> 8Transversity Analysis Meeting
SSA difference
•Red: MLE Final•Blue: Blue team Final
•Difference could be40% of σ for 1 term fit•2 term fit is more consistent:
Jin Huang <[email protected]> 9
The event list is very close Method
1. Combine Spin States: Local Pair VS MLE Results have difference We know MLE is more sensitive to yield drifts Believe Local Pair method is better for Pion analysis
2. Extract Angular Modulation: Angular Fit VS MLE Believe to be equivalent @ large stat. (ex. (e’pi))
Indirectly tested on DSA Tested for both 1 term 1D fit and 2 term 2D fit
Xin showed that at low stat. (ex. (e’K)), MLE have better statistic precision
Transversity Analysis Meeting
SSA difference is understood
Jin Huang <[email protected]> 10
Raw SSA Based on very similar data set
Difference believed to be from different way combining local spin states
Transversity Analysis Meeting
DIFFERENCE in combining spin states
Jin Huang <[email protected]> 11
Indirectly checked by fitting sin(phi_h±phi_S) on DSA:
Transversity Analysis Meeting
CONSISTENCY in Angular Modulation Extraction
Jin Huang <[email protected]> 12
Difference on Method ◦ Blue team Fit method is better for Pion SSA
analysis◦ MLE method is better for Kaon SSA/DSA analysis◦ Both MLE/Fit methods OK for DSA pion analysis
Difference on Cut/Run List ◦ Remove Extra 17 Problematic Runs (L1A/DMA/…
problem) identified by blue team◦ 8 Runs with low LT remain off from MLE run list.
OK for blue team method (local pair with in these runs)
◦ Remove “LHRS pion rejecter response>0” cut 3~4% more event in statistic
◦ Other difference on Cut/Variable use are negligible
Transversity Analysis Meeting
Difference understood &Suggestion on addressing them