1. Lambda hypernuclear spectroscopy up to medium heavy mass number at JLab Hall-C Graduate school of Science, Tohoku Univ. Toshiyuki Gogami

2. Contents Introduction Experimental setup Analyses Missing mass Summary

3. Contents Introduction Experimental setup Analyses Missing mass Summary ee u u d u s s u d – p K+K+ Λ γ*γ* (e,e’K + ) reaction

4. Λ hypernuclear spectroscopy Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564. 52  V

5. Spectroscopic experiment by the (e,e’K + ) reaction p n γ*γ* Λ K+K+ e-e- e + p ➝ e’ + K + + Λ target nucleus ~ 1990’s The (K -,π - ), (π +,K + ) reactions Energy resolution ~ a few MeV n  Λ e’-Spectrometer K + -Spectrometer p e’ p K+ Missing Mass M HY 2000~ The (e,e’K + ) reaction Energy resolution ~0.5 MeV p  Λ

6. Experimental motivation JLab E05-115 (2009, Hall-C) – Elementary processes (Λ,Σ 0 ) – 7 Λ He [1], 9 Λ Li, 10 Λ Be ΛN charge symmetry breaking ΛN-ΣN coupling – 12 Λ B [2][3][4] Consistency check with the past experiments Check analysis progress – 52 Λ V Single particle energy For measurements with heavier targets [1] S.N.Nakamura et al., PRL 110, 012502 (2013) [2] T.Miyoshi et al., PRL 90, 232502 (2003) [3] L.Yuan, PRC 73, 044607 (2006) [4] M.Iodice, PRL 99, 052501 (2007)

7. Contents Introduction Experimental setup Analyses Missing mass Summary HES

8. Experimental setup (E05-115 @ JLab Hall-C)

9. Contents Introduction Experimental setup Analyses Missing mass Summary

10. Analysis

11. x, x’, y, y’ p, x’, y’ @ Reference plane @ Target Missing Mass

12. Energy scale calibration e, K + Polyethylene target (0.45 g/cm 2 ) FWHM ~ 1.8 MeV

13. Contents Introduction Experimental setup Analyses Missing mass Summary

14. 10 Λ Be, 12 Λ B histograms N sΛ ~190 sΛsΛ pΛpΛ FWHM~0.9 MeV N sΛ ~530 sΛsΛ Preliminary T.Motoba et al., PTP Supplement 185 ( 2010 ) Analyses are in progress to achieve better energy resolution with keeping good linearity. Analyses are in progress to achieve better energy resolution with keeping good linearity.

15. Summary and outlook JLab E05-115 (2009) – Λ, Σ 0, 7 Λ He, 9 Λ Li, 10 Λ Be, 12 Λ B, 52 Λ V – Analyses are in progress Matrix tuning Blind analysis Efficiencies

16. E05-115 collaboration

17. Backup

18. New challenging experiment  Λ, Σ 0  Elementary process  Energy scale calibration  12 Λ B  Consistency check  27 Λ Mg, 48 Λ Sc  Deformation  208 Λ Tl  Single particle energy 1m p n γ*γ* Λ K+K+ e-e- target nucleus

19. New challenging experiment  Λ, Σ 0  Elementary process  Energy scale calibration  12 Λ B  Consistency check  27 Λ Mg, 48 Λ Sc  Deformation  208 Λ Tl  Single particle energy  4 Λ H  Charge symmetry breaking 1m p n Λ π-π- target nucleus

20. New challenging experiment  Λ, Σ 0  Elementary process  Energy scale calibration  12 Λ B  Consistency check  27 Λ Mg, 48 Λ Sc  Deformation  208 Λ Tl  Single particle energy Design and setup 3-D magnetic field calculation Monte Carlo simulation Experimental operation Analyses Energy scale calibration Tracking 1m  4 Λ H  Charge symmetry breaking

21. Background events in the HKS z [cm] y [cm] x [cm] KDC1 KDC2 KDC1 KDC2 9 Be, 38.4 [μA] REAL DATA SIMULATION e+e+ 52 Cr target – Luminosity ( 1/10 ) – Worse S/N – Tracking is not easy

22. Tracking efficiency and residual σ ~ 160 μm Plane efficiency Tracking residual σ ~ 350 μm

23. 52 Cr(e,e’K + ) 52 Λ V Preliminary N bind ~870

24. Hit wire selection REAL DATA Black : hit wires Blue : selected wires Red : track 52 Cr Target REAL DATA CH 2 Target Compared to the conventional code  Number of K + +130%  Analysis time – 30% CUT

25. 軽い核のミッシングマス 数、分解能 JLab E05-115, Carbon (112mg/cm 2 )

26. Energy scale calibration e, K + conversion Mx – MΛ < 100 keV/c2

27. トラッキング困難 REAL DATA Black : hit wires Blue : selected wires Red : track CH 2 Target H 2 O Target

28. 52LV

29. Singles rate summary Up to ~30 [MHz] Up to ~15 [MHz] HES HKS HKS trigger ~ 10[kHz] HES trigger ~ a few[MHz] HKS-HES Collaboration Meeting, T.Gogami29

30. B.G. mix rate (real data) a b * hks ntulpe HKS-HES Collaboration Meeting, T.Gogami30

31. e + simulation SIMULATION To see 1.Number of event 2.Angle & momentum of e + generated in target To see 1.Number of event 2.Angle & momentum of e + generated in target HKS-HES Collaboration Meeting, T.Gogami31

32. Spectroscopic experiment by the (e,e’K + ) reaction p n γ*γ* Λ K+K+ e-e- e + p ➝ e’ + K + + Λ ee target nucleus Feynman diagram u u d u s s u d – p K+K+ Λ γ*γ* ~ 1990’s The (K -,π - ), (π +,K + ) reactions Energy resolution ~ a few MeV n  Λ e’-Spectrometer K + -Spectrometer p e’ p K+ Missing Mass H HY 32 2000~ The (e,e’K + ) reaction Energy resolution ~0.5 MeV p  Λ 2012/9/14JPS meeting in Kyoto, Toshi Gogami

33. Background events in the HKS z [cm] y [cm] x [cm] KDC1 KDC2 KDC1 KDC2 9 Be, 38.4 [μA] REAL DATA SIMULATION ~2.24 ~4.94 e+e+ 52 Cr target – Luminosity ( 1/10 ) – Worse S/N – Tracking is not easy

34. 10 Λ Be, 12 Λ B histograms N sΛ ~190 sΛsΛ pΛpΛ FWHM~0.9 MeV N sΛ ~530 sΛsΛ Preliminary

35. Experimental motivation JLab E05-115 (2009, Hall-C) – Elementary processes (Λ,Σ 0 ) – 7 Λ He [1], 9 Λ Li, 10 Λ Be ΛN charge symmetry breaking ΛN-ΣN coupling – 12 Λ B Consistency check with the past experiments Check analysis progress – 52 Λ V Single particle energy (systematic な study) ls splitting, core-configuration mixing 将来重く行くため避けられない道 [1] S.N.Nakamura et al., PRL 110, 012502 (2013)

36. Detectors & Trigger K + p, π + e-e- Drift chambers TOF walls (Plastic scintillators) Cherenkov detectors Aerogel (n=1.05) Water (n=1.33) HES HKS HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HES trigger (TOF1x2) ~2000 kHz HES trigger (TOF1x2) ~2000 kHz Coincidence trigger HES x HKS < 2 kHz Coincidence trigger HES x HKS < 2 kHz 2012/10/6Core2Core in Barcelona, Toshi Gogami36

37. 52 Cr(e,e’K + ) 52 Λ V Mixed event analysis をやる s p d f 数 Preliminary

38. Electro-production of K + Λ JLab E05-115 experiment by the (e,e’K + ) reaction Small Q 2 ( ~0.01 [GeV/c] 2 )  almost real photon Real photon 2013/3/27JPS meeting in Hiroshima, Toshi Gogami38

39. An importance of measurement of K + Λ production at forward angles At forward angles – Data show lack of consistency – We can access θ K cm ~ 15 deg P.Bydzovsky and T.Mart, Phys. Rev. C 76, 065202 (2007) 2013/3/27JPS meeting in Hiroshima, Toshi Gogami39 Real photon Q 2 = 0 [ GeV/c ] 2

40. Λ, Σ 0 from polyethylene ( CH 2 )target JPS meeting in Hiroshima, Toshi Gogami 2013/3/27 Preliminary 40

41. Λ, Σ 0 from CH 2 target JPS meeting in Hiroshima, Toshi Gogami 2013/3/27 Preliminary 41 p(e,e’K + )Λ ~1.8MeV (FWHM) Δm = 19 ± 17 keV/c 2 p(e,e’K + )Σ 0 ~1.8MeV (FWHM) Δm = 73 ± 47 keV/c 2 JLab E05-115 CH 2, ~ 450 [mg/cm 2 ] ~ 2.0 [μA] ~ 38 [hours]

42. Cross sections 2013/3/27JPS meeting in Hiroshima, Toshi Gogami42 SAPHIR : K.H. Glander et al., Eur. Phys. J. A 19, 251-273 (2004) CLAS : R. Bradford et al., Phys. Rev. C 73, 035202 (2006) γ (*) + p  K + + Λ γ (*) + p  K + + Σ 0 Preliminary 200 ± 16 ± 91 Preliminary 85 ± 13 ±34

43. Cross sections 2013/3/27JPS meeting in Hiroshima, Toshi Gogami43 SAPHIR : K.H. Glander et al., Eur. Phys. J. A 19, 251-273 (2004) CLAS : R. Bradford et al., Phys. Rev. C 73, 035202 (2006) JLab E94-107 : P. Markoviz et al., Proceedings of SENDAI08 (2009) JLab E91-016 : F. Dohrmann et al., arXiv 0707.3059v2 (2007) γ (*) + p  K + + Λ γ (*) + p  K + + Σ 0 Preliminary 200 ± 16 ± 91 Preliminary 85 ± 13 ±34

44. Q 2 dependence (JLab E05-115) JLab E05-115, CH 2 target Preliminary 2013/3/27JPS meeting in Hiroshima, Toshi Gogami44 W = 1.93 GeV θ CM = 17 degrees W = 1.93 GeV θ CM = 17 degrees 実光子 (SAPHIR)

45. Apply to u,v-layer Applied to uu’ and vv’ layers, too. Selective region determined by 1X and 2X Convert v v’-layer x x’-layer JPS meeting in Kyoto, Toshi Gogami452012/9/14

46. Hit wires event display (2) GREEN region Selective region RED markers & lines Selected hit wires BLACK markers & lines Rejected hit wires v v’ u u’u u’ x x’ v v’ u u’u u’ x x’ KDC1 KDC2 particle JPS meeting in Kyoto, Toshi Gogami462012/9/14

47. Detectors & Trigger K + p, π + e-e- Drift chambers TOF walls (Plastic scintillators) Cherenkov detectors Aerogel (n=1.05) Water (n=1.33) HES HKS 2012/10/6Core2Core in Barcelona, Toshi Gogami47

48. Detectors & Trigger K + p, π + e-e- Drift chambers TOF walls (Plastic scintillators) Cherenkov detectors Aerogel (n=1.05) Water (n=1.33) HES HKS HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HES trigger (TOF1x2) ~2000 kHz HES trigger (TOF1x2) ~2000 kHz Coincidence trigger HES x HKS < 2 kHz Coincidence trigger HES x HKS < 2 kHz 2012/10/6Core2Core in Barcelona, Toshi Gogami48

49. Coincident K + Identification (OFF-LINE) 2012/10/6Core2Core in Barcelona, Toshi Gogami49 Cherenkov selection Coincidence time selection Aerogel (n=1.05) Water (n=1.33) K+K+ π+π+ p CUT p cutπ + cut = HKS T - HES T ( e,e’p ) ( e,e’π + ) CUT ( e,e’K + ) Coincidence of (e,e’K + ) selection CUT m K 2 selection Coincident K + : ~90% ( π + : < 1%, p : < 2% )

50. 10 Λ Be, 12 Λ B histograms N sΛ ~190 sΛsΛ pΛpΛ FWHM~0.9 MeV N sΛ ~530 sΛsΛ Preliminary