jin huang, xin qian for transversity analysis meeting may 3, 2010
DESCRIPTION
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 3TRANSCRIPT
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