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E01-011 Analysis update Adjust of the Splitter-HKS Side

E01-011 Analysis update Adjust of the Splitter-HKS Side. Yuncheng Han May 09, 2012 Hampton University JLab hypernuclear collaboration meeting. Outline. Overview of the E01-011 experiment Principle of the forward optics tune Methods of the optical matrix modification

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E01-011 Analysis update Adjust of the Splitter-HKS Side

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  1. E01-011 Analysis updateAdjust of the Splitter-HKS Side Yuncheng Han May 09, 2012 Hampton University JLabhypernuclear collaboration meeting

  2. Outline • Overview of the E01-011 experiment • Principle of the forward optics tune • Methods of the optical matrix modification • Further optimize the optical matrices from focal plane to sieve slit plane • Status using the new optical matrices

  3. Overview of the E01-011 Experiment Carried out at JLab in 2005, to obtain high resolution, high yield rates hypernuclear spectroscopy, for study of hyperon-nucleon interaction. e’ Target N e /0 γ* p K+ e + p → / 0+ e’+ K+ e + N → N+ e’+ K+ Three generations : E89-009 (2000), E01-011 (2005), E05-115(2009)

  4. -6.730.020.2 MeV The Results of E01-011 Experiment HKS JLAB 28Al d p 7He s Counts (150 keV/bin) 7He: 1st time w/ high statistics; BΛ and feature confirmed; Paper drafted: n-halo state, CSB. FWHM ~500 keV 28Al :1st medium-heavy hyper-nuclear spectrum w/ clear s-, p-, d-shell state peaks; space of s- and p- shell states 1~2 MeV wider but p- and d- shell states ~1 MeV narrower than expected 12B B (MeV) 12B : consistent of JLab E89-009; much better resolution.

  5. The Status of E01-011 Experiment • Data analysis was already done, 7He, 12B, 28Al; • However, the splitter magnet actual current in this exp was 8.5 % bigger than the designed value, which made the real optics different a lot from the designed one. The previous analysis used the designed optics as an initial, and relying on mathematical method (nonlinear χ2fit ) for optimization; • Freedom of the mathematical tune is large (1260 elements in the optics matrices), so the reliability of the final results was not solid; • Since the fringe field near the splitter magnet region introduce asymmetry to the magnetic field map, a better optics can be gotten if consider the asymmetry.

  6. Previous analysis method Field map Backward tune Nonlinear least χ2 fitting kinematical scan Geant3 Exp.data Final matrices Initial optics matrices Λ-hypernuclear spectroscopy CH2 data Tuned matrices Λ &Σ0mass spectroscopy Kinematics: masses and emit angles of Λ & Σ0 Mathematical tune of optics matrices

  7. New Analysis method Qualifications of A, B and C Magnetic field study Field map Geant3 simulation Sim focal plane distribution A B Reconstructed sieve slit distri Exp data Exp focal plane distribution Optical matrices C Sieve slit geometry Mass/angle independence Calculated Λ/Σ spectroscopy

  8. Relationship between sieve slit and focal plane Sieve Slit Focal Plane Target Q1-Q2-Dipole Splitter K+

  9. Strategy of introduce new optics • New optical matrices was introduced to satisfy • Focal plane distribution sim match exp data • Reconstructed sieve slit distribution match • real sieve slit geometry • Calculated masses independent on • kinematical parameters of kaons (p, X’, Y’) • New optical matrices was gotten by • Introduce asymmetry function to • the magnetic field map • offset of the field map geometry • Adjust position of focal plane Sieve Slit Focal Plane Target Q1-Q2-Dipole Splitter K+ Focal plane position 235 cm to 265 cm Chambers’ distance 100 cm to 36 cm

  10. Splitter asymmetry

  11. Q1 asymmetry

  12. Q2 asymmetry

  13. Dipole asymmetry

  14. Comparison of focal plane/sieve slit distribution • FP Y-X • Sieve Slit FP X’-X W/ initial optical matrices W/ new optical matrices

  15. Comparison of mass dependence on kinematics • W/ initial optical matrices W/ new optical matrices

  16. Further optimize the optical matrices Region of one hole Center of the hole (X-X0)2 + (Y-Y0)2 < R2 (X0,Y0)

  17. Masses and emit angles of Λ/ w/ new matrices

  18. Comparison of Λ/0mass spectrum Mathematical method (nonlinear least χ2fit ) • W/ initial optical matrices W/ new optical matrices

  19. Comparison of 12B mass spectrum 12B Δ ~ 10.97 MeV Δ ~ 10.79 MeV Δ ~ 11.05 MeV Δ ~ 11.64 MeV

  20. Summary • E01-011 experiment was carried out in 2005 at JLab, analysis was already done, 7He, 12B, 28Al; • Initial optical matrices was poor, by introduce scaling asymmetry function, offset field map geometry, and adjust position of focal plane, new optical matrices for Splitter-HKS side was obtained; • Quality of Λ/0 spectrum w/ new optical matrices is already comparable of previous finalized results; • 12B mass spectrum was checkedw/ new optical matrices ; • New optical matrices for electron arm will be tune soon • More reliable and higher quality results are expected with the new optical matrices (for both electron arm and kaon arm) and the powerful nonlinear least χ2fit mathematical tune.

  21. Residual of present optical matrices

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