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Data Analysis (ODU) and Simulations (J. Udias, Madrid)

Data Analysis (ODU) and Simulations (J. Udias, Madrid). Outline Introduction Hall A and Electron Scattering Experiment Goals and Kinematics Setup Data Analysis Good Runs, Target Foils, TOF, Acceptance Comparing to Previous Work R-Function and Results Summary and What’s Next?.

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Data Analysis (ODU) and Simulations (J. Udias, Madrid)

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  1. DataAnalysis (ODU) and Simulations (J. Udias, Madrid)

  2. Outline • Introduction • Hall A and Electron Scattering • Experiment • Goals and Kinematics Setup • Data Analysis • Good Runs, Target Foils, TOF, Acceptance • Comparing to Previous Work • R-Function and Results • Summary and What’s Next?

  3. Electron-Nucleus Interactions • Three cases: • Low q • Photon wavelength  larger than the nucleon size (RN) • Medium q: 0.2 < q < 1 GeV/c •  ~ RN • Nucleons resolvable • High q: q > 1 GeV/c •  < RN • Nucleon structure resolvable Energy vs Spatial Resolution • Select spatial resolution and excitation energy independently • Photon energy  determines excitation energy • Photon momentum q determines spatial resolution   hbar/q

  4. Diagram of A(e,e’p) Missing Energy: Em =  - Tp – TR Missing Momentum: pm = q – p’ 4-vector transferred mom: Invariant : Q2 = 4EiEfsin2(e/2)

  5. Outline • Introduction • Hall A and Electron Scattering • Experiment • Goals and Kinematics Setup • Data Analysis • Good Runs, Target Foils, TOF, Acceptance • Comparing to Previous Work • R-Function and Results • Summary and What’s Next?

  6. Goals of E00102 • Measurement of cross-section, RLT and ALT for the 16O(e,e’p) reaction with higher precision and to higher missing momentum than in E89003. • Determine the limit of validity of the single-particle model of valence proton knock-out. • Determine effects of relativity and spinor distortion on valence proton knock-out using the diffractive character of the ALT symmetry. • Determine bound-state wave function and spectroscopic factors for valence proton knockout.

  7. E00102Kinematics • Kin Settings • 9 “Negative” Kins • 11 “Positive” Kins • 1 Parallel Kin • Statistics • Total : 1743 runs • Good (77%) • Fixable (4%) • Calibration (6%) • Bad Runs (13%)  +

  8. mm mm 28o – 96o

  9. Outline • Introduction • Hall A and Electron Scattering • Experiment • Goals and Kinematics Setup • Data Analysis • Good Runs, Target Foils, TOF, Acceptance • Comparing to Previous Work • R-Function and Results • Summary and What’s Next?

  10. Determining “Good” Runs For Kin AA+ Fixable T1/T3 Good Runs Bad Runs coll 6msr coll open RUNNO T1 = Proton Rates T3 = Electron Rates

  11. How We Handle Targets Kin AA+ Uncut CTOF cut Foil 3 Foil 2 Foil 1

  12. Time of Flight : Kin AA- (1531) 2 1 3 Region A

  13. Missing Energy Spectra : Kin AA- (1531) 1P3/2 1P1/2 Events Mistiming factor True = Real–2 Accidental (1+ 3)

  14. 1P1/2 Relative Cross SectionComparing to Previous Results* • Determination of 1P1/2 cross section relative to H(e,e’) Only used central target foils ! * M. Anderson, Licentiate Thesis October 2005

  15. Relative Cross Section • Cross Section : 16O(e,e’p) : H(e,e’) : • Relative Cross Section : No L !

  16. Data • Replayed good runs • Implemented energy loss correction • Studied CTOF, zreact, acceptances, Emiss, Pmiss, mistiming factor correction, etc. • Applied angular cuts :  (±50 mr) and  (±25 mr) • Applied momentum cuts :  (±3.5%) • Applied background subtraction.

  17. Simulation • Bound states physics models – calculated by Madrid Group. • Spectrometer models – ON, radiative effects – ON, and energy loss correction – OFF • Use the same acceptance values (,,and ) as in data. • Use target configuration that built into the MCEEP.

  18. Recipe relative for 1P1/2 • Apply cuts on tg, tg, zreact, CTOF (Region A), and Emiss. • Subtract CTOF background bin-by-bin. • Apply mistiming correction factor • Normalize to 1H(e,e’)luminosity • Normalize to MC phase-space • Divide each data point by pmiss bin width

  19. relative for 1P1/2 (Central Foils) Previous Work dhfkjklll Pmiss (MeV/c)

  20. relative for 1P1/2 (Central Foils) This Work AA- AA+ DD+ DD- Pmiss (MeV/c)

  21. R-Function Maximize Event Acceptance • Determine nominal acceptance boundaries (tg, tg, ) for each HRS. • R-function measures distance (+/-) to boundary of each trajectory : 1. R < 0.0  outside 2. R >= 0.0  inside • Choose cut to make on R a. where we understand the acceptance b. Maximize it tg tg R-arm Kin AA- (1531)

  22. R-Functions of Kin AA+ (1315) R-Arm L-Arm Red (Data) and Blue (Simulation)

  23. Where to R-Function Cuts? (Kin AA+) R-Arm L-Arm

  24. Value of R-Function Cuts Next plots four different conditions of R-cut are used: • No R-cut (uncut) • R > 0.0 • R > 0.005 • R > 0.01

  25. L-Arm Acceptance with 3-foils : Kin AA+ R > 0.0 R > 0.005 R > 0.01 Uncut

  26. R-Arm Acceptance with 3-foils : Kin AA+ R > 0.0 R > 0.005 R > 0.01 Uncut

  27. Missing Momentum : Kin DD+ (1497) Uncut R > 0.0 R > 0.01 R > 0.01 R > 0.005 R > 0.005

  28. Outline • Introduction • Hall A and Electron Scattering • Experiment • Goals and Kinematics Setup • Data Analysis • Good Runs, Target Foils, TOF, Acceptance • Comparing to Previous Work • R-Function and Results • Summary and What’s Next?

  29. Summary and What’s Next? • Intensive studies to understand both data and simulation has been performed. Treatment for both data and simulation is better understood. • All three foils cut would be used (previous work only used the central foils). • R-function is now better understood and will be implemented as the acceptance cut for both data and simulations. • Ready to replay to all different sets of kinematics and ready to fix/save runs (to gain better statistics). • Plan to perform the reduced cross section and make plots of red versus pmiss for available replayed runs in each kinematics.

  30. THANK YOU,ANY QUESTION ?

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