E Analysis update Adjust of the Splitter-HKS Side Yuncheng Han May 09, 2012 Hampton University JLab hypernuclear collaboration meeting

Outline Overview of the E 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 2

Overview of the E Experiment Carried out at JLab in 2005, to obtain high resolution, high yield rates hypernuclear spectroscopy, for study of hyperon-nucleon interaction. e + p →   + e’   Target N e + N →   + e’   e γ*γ* e’ K+K+ p   Three generations : E (2000), E (2005), E05-115(2009) 3

The Results of E Experiment  0.02  0.2 MeV 7  He FWHM ~500 keV 12  B 12  B : consistent of JLab E89-009; much better resolution. 28  Al :1 st 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 7  He: 1 st time w/ high statistics; B Λ and feature confirmed; Paper drafted: n-halo state, CSB. B  (MeV) HKS JLAB Counts (150 keV/bin) ss pp dd 28  Al

The Status of E 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 χ 2 fit ) 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. 5

Previous analysis method Nonlinear least χ 2 fitting kinematical scan Geant3 CH 2 data Λ & Σ 0 mass spectroscopy Field map Kinematics: masses and emit angles of Λ & Σ 0 Mathematical tune of optics matrices Initial optics matrices Initial optics matrices Tuned matrices Exp. data Backward tune Λ-hypernuclear spectroscopy Final matrices 6

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

Relationship between sieve slit and focal plane Target Splitter Sieve Slit Q1-Q2-Dipole Focal Plane  8

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 Strategy of introduce new optics 9 Target Splitter Sieve Slit Q1-Q2-Dipole Focal Plane  Focal plane position 235 cm to 265 cm Chambers’ distance 100 cm to 36 cm

Splitter asymmetry

Q1 asymmetry

Q2 asymmetry

Dipole asymmetry

FP X’-X FP Y-XSieve Slit Comparison of focal plane/sieve slit distribution 14

Comparison of mass dependence on kinematics 15

16 Region of one hole Center of the hole (X-X 0 ) 2 + (Y-Y 0 ) 2 < R 2 (X 0,Y 0 ) Further optimize the optical matrices

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

Comparison of Λ/  0 mass spectrum 18

19 12  B Δ ~ MeV Δ ~ MeV Δ ~ MeV Δ ~ MeV Comparison of 12  B mass spectrum

Summary E 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 checked w/ 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 χ 2 fit mathematical tune. 20

21 Residual of present optical matrices

22 Comparison of focal plane X-Y distribution Blue: simulation ; Red: experimental data

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The Status of E Experiment Analysis was already finished, and get fruitful results. 25 B  (MeV) 28 Si(e, e’K + ) 28  Al (JLab Hall C E01-011) HKS JLAB Counts (150 keV/bin) 28  Al ss pp dd -B  (MeV)  0.02  0.2 MeV from  n n 7  He 7 Li(e, e’K + ) 7  He (JLab Hall C E01-011) 7  He: 1 st time w/ high statistics; B Λ and feature confirmed; Paper drafted: n-halo state, CSB. 12 C(e, e’K + ) 12  B (JLab Hall C E01-011) ~500 keV FWHM 12  B 12  B : consistent of JLab E89-009; much better resolution. 28  Al :1 st observed medium heavy hypernuclear spectroscopy w/ clear s-, p-, d-shell state peaks; distance of s- and p- shell states 1~2 MeV wider but p- and d- shell states ~1 MeV narrower than expected

Sieve Slit using in E01-011