HES-HKS analysis meeting

1. HES-HKS analysis meeting Toshiyuki Gogami 10Jan2014

2. Contents • About missing mass resolution • Blind analysis • Resolution and linearity balance • Response function • Missing mass status • Binding energy and cross section • 12ΛB, 10ΛBe and 7ΛHe

3. Missing mass estimation by the full-modeled Monte Carlo simulation

4. Achievable resolution ( FWHM, Unit: keV ) Part of the z-dependence (Λ, Σ0 and 12ΛB) is absorbed by the matrices in a matrix tuning.  Effects of z-dependence absorption for other hypernuclei are not trivial.  Blind analysis

5. Blind analysis • Width and linearity balance • Matrix z-dependence (Λ,Σ0) absorption effect for hypernuclei • Response function

6. Flow chart Initial matrices (not distorted) Generated Λ, Σ0 and hypernucei Λ + B.G. Σ0 + B.G. 12ΛB s-shell Tune Compare after tuning Tuned matrices Λ, Σ0 and hypernucei • Absorbing effects of • z-dependence • Asymmetry shape • Etc.

7. Λ + B.G. Σ0 + B.G. 12ΛB s-shell Results No matrix distortion + Mean value displacement Width Λ, Σ0 Λ, Σ0 Λ, Σ0, 12ΛB FWHM [keV] ΔMM [keV] Λ, Σ0, 12ΛB 500 ~ 700 keV (12ΛB, 10ΛB, 52ΛV) ~ 1000 keV (7ΛHe) ~ 1500 keV (Λ, Σ0) ΔMM < 130 keV Achievable resolutions Achieved simultaneously !

8. Response function

9. Missing mass status • 12C(e,e’K+)12ΛB • 7Li(e,e’K+)7ΛHe • 10B(e,e’K+)10ΛBe • 9Be(e,e’K+)9ΛLi • 52Cr(e,e’K+)52ΛV

10. 12C(e,e’K+)12ΛB

11. 7Li(e,e’K+)7ΛHe

12. 10B(e,e’K+)10ΛBe

13. 9Be(e,e’K+)9ΛLi Accidental background

14. 52Cr(e,e’K+)52ΛV

15. Binding energy and Cross section • About cross section • Definition • Cut conditions • Efficiencies and correction factors • Results • 12C(γ*,K+)12ΛB • 7Li(γ*,K+)7ΛHe • 10B(γ*,K+)10ΛBe

16. Definition of differential cross section Number of target protons Efficiencies HKS acceptance Number of virtual photon including HES acceptance

17. Cut conditions • 0.80 < pe < 0.98 [GeV/c] • Abs(m2-m2K) < 0.3 • -1.0 < ctime < 1.0

18. Efficiencies and correction factors • Efficiencies • DAQ • Trigger • Tracking • K+ selection • AC, WC, m2, • Correction factors • K+ decay (momentum dependent) • Solid angle (momentum dependent) • K+ absorption • Event loss due to matrix and large energy loss (not included for the present work) • Already studied by Fujita ~ 5- 10%

19. 12C target • Remarks • Efficiencies are different between low and high current data • Two set of HES collimator positions are used.

20. Differential cross section of 12C(γ*,K+)12ΛB ( FWHM ~ 0.89 MeV ) Only statistical errors

21. 12ΛB comparison SΛ pΛ

22. 7Li target • Remarks • Target thickness (Three values) • Shichijo: 184.0 mg/cm2 • ELOG • Weight and area: 331.2 mg/cm2 • Oil ? Nitriding ? • Thickness and density: 207 mg/cm2 • Nitriding test • Check Brems. Rate in HES • Etc. Need to be done !!!!

23. Differential cross section of 7Li(γ*,K+)7ΛHe ( FWHM ~ 1.3 MeV )

24. 7ΛHe comparison ( FWHM ~ 1.3 MeV ) -5.36 without CSB -5.16 with CSB (FWHM ~ 1.3 MeV) Hiyama’s calc.

25. 10B target

26. Differential cross section of 10B(γ*,K+)10ΛBe ( FWHM ~ 0.8 MeV )

27. Comparison with old data MeV

28. Differential cross section of 10B(γ*,K+)10ΛBe Motoba’s calc. ( FWHM ~ 0.8 MeV ) -8.84 without CSB -8.76 with CSB Hiyama’s calc.

29. 9Be(γ*,K+)9ΛLi (only figure)

30. Summary • Estimated missing mass resolution • Blind analysis • Resolution and linearity balance • Response function • Missing mass status • Binding energy and cross section • 12ΛB, 10ΛBe and 7ΛHe

31. Backup

32. Expected achievable missing mass resolution • 分解能の表 • 各寄与 • Z-depenenceを引いた後に残る分解能 Tuningでz-dependenceを吸収  Resolution ? Linearity? Blind analysis (next)