1. Positron Asymmetry and Polarization from the E166 September 2005 run Gideon Alexander, Erez Reinherz-Aronis

2. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis General In the analysis we considered only the Central Crystal (Crystal #5) We adopted the approach that by chaining all runs together the local variations are averaged out.

3. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Selection of Runs and Events 1 st stage:  SuperRuns.  Runs with Spectrometer and Lens values  Runs were rejected when  Empty runs.  Beam off.  15 Hz runs. Spectrometer [A]100120140160180 Lens [A]220260340360374 Positron energy [MeV]3.654.385.115.846.57

4. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Selection of Runs and Events 2 nd stage : Pairs of events were accepted by  ‘Trigger' word*.  ‘Latch' word*. *These are a result of a careful study of the 'agup', 'x5_1[0]' and 'x5_1[1] variables. Note: Events with ADC above 4000 were filtered out.

5. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Selection of Runs and Events 2 nd stage : Pairs of events were accepted only if  ‘Trigger' word - ‘Signal’ = 36864 ‘Background’= 36896  ‘Latch' word values: 1320, 1800, 1832, 2824, 2856, 3336, 3368, 3848, 3880, 3898, 4904, 5416, 5928, 6440, 6952, 7432, 7464, 7944, 7976, 7962, 7994. *These are a result of a careful study of the 'agup', 'x5_1[0]' and 'x5_1[1] variables. Note: Events with ADC above 4000 were filtered out. Backup 0

6. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Looking at the data Convert the root files  Magnet data is out.  Branches added:  polarity, cycle, runnumber.  signal+bg event & bg event – parallel “Old event”s: (signal+bg) or (bg) “New event”: (signal+bg, bg) Backup 1

7. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Cycle 0 Magnet polarity polaritycycle Signal + BgBg Signal + BgBg Signal + BgBg Signal + BgBg Data – signal + bg. Data – bg. Data – signal + bg. Data – bg.... Cycle 1 Magnet polarity Data – signal+bg Data – bg Data – signal+bg Data – bg... Cycle 2..... “new” Event Backup 2

8. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Use of the toroid 6130 The toroid currents was used to define the appropriate range of the data. Taking ±2σ range from an overall Gaussian fit. The analysis was then carried out with and without a Toroid normalization.

9. Positron Asymmetry Event Pair : Signal*, Background (Bg). Gaussian Fit in general is poor we use it only to define the sample rage. For each spectrometer value we calculate L and R *Signal = Signal over Background (Signal + Bg)

10. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Asymmetry Error For a Gaussian distribution:

11. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Asymmetry Error Note: Gaussian Fit in general is poor Calculate Sigma by so the Asymmetry error can be written as

12. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Gain 1, Low sensitivity (12 bit)

13. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Gain 1, High sensitivity (15 bit)

14. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Positron Asymmetry

15. Positron Polarization A e + (extract) from Table 13, E-166 Proposal, June 2003. ~0.073

16. Positron Asymmetry and Polarization from the E166 September 2005 run Prof. Gideon Alexander, Erez Reinherz-Aronis

17. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis

18. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis

19. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis CsI Analyzing magnet (-60/+60) W-Target Lens SpectrometerSpectrometer e-e- e-e- e-e- γ γ Undulator Bend magnets SLC e-e- e-e- Analyzing magnet (-60/+60) γ detectors E-166 @ FFTB (SLAC) Backup 3

20. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Backup - values for Polarization Spectrometer [A]Ee+Ee+ Ae+Ae+ 1003.650.1931 1204.380.1867 1405.110.1688 1605.840.1600 1806.570.1585 Backup 4 A e + (extract) from Table 13, E-166 Proposal, June 2003 (Averages).

21. E-166 - Princeton, May 2006 Gideon Alexander Erez Reinherz-Aronis Backup – Toriod cuts Spectrometer [A]Low limitHigh limit 100490550 120500520 120520570 140480538 140538600 160530567 180525565 electrons500520 electrons520550 electrons560590 Backup 5