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JLab に おける高品質電子ビームを用いた ラムダハイパー核分光実験の解析状況

14aSC-4. Graduate school of science, Tohoku University Toshiyuki Gogami for the HES-HKS collaborations. JLab に おける高品質電子ビームを用いた ラムダハイパー核分光実験の解析状況. JLab Hall-C (2009). Contents Introduction Experimental setup K + Λ electro-production Summary.

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JLab に おける高品質電子ビームを用いた ラムダハイパー核分光実験の解析状況

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  1. 14aSC-4 Graduate school of science, Tohoku University Toshiyuki Gogami for the HES-HKS collaborations JLabにおける高品質電子ビームを用いたラムダハイパー核分光実験の解析状況 JLab Hall-C (2009) Contents Introduction Experimental setup K+Λ electro-production Summary JPS meeting in Kyoto , Toshi Gogami

  2. Spectroscopic experiment by (e,e’K+) reaction pe’ e + p➝ e’ + K+ + Λ Feynman diagram e- e’-Spectrometer e e u u γ* K+ – γ* u s Coincidence p Missing Mass HHY d s p K+ u Λ Λ d n K+-Spectrometer pK+ target nucleus • ~ 1990’s • (K-,π-) , (π+,K+) reactions • Energy resolution ~ a few MeV • n Λ • 2000~ • (e,e’K+) reaction • Energy resolution ~500keV • p  Λ JPS meeting in Kyoto , Toshi Gogami

  3. E05-115 experimental motivation • 2009 Aug – Nov @ JLab Hall-C • (e,e’K+) reaction • Target : 7Li , 9Be , 10B , 12C , 52Cr It is difficult experimentally. “ b.g. electron due to brems. ∝ ~Z2 “ First try • Light Λhyprenuclei(7He,9Li,10Be,12B) • Charge symmetry breaking • Λ-Σ coupling Λ Λ Λ Λ • Medium heavy Λ hyprenuclei(52V) • s-,p-,d-,f-orbit binding energy • & cross section • Mass dependence of Λ single particle energy • l・s splitting　∝ 2l+1 Λ BΛ[MeV] • Λ, Σ0 • Energy scale calibration • Elementary process A = 52 JPS meeting in Kyoto , Toshi Gogami

  4. Electro-production of K+Λ JLab E05-115 experiment by the (e,e’K+) reaction Small Q2 ( ~0.01 [GeV/c]2 )  almost real photon Real photon JPS meeting in Kyoto , Toshi Gogami

  5. An importance of measurement of K+Λproduction at forward angles At forward angles • Data show lack of consistency • We can access θKcm ~ 15 deg P.Bydzovsky and T.Mart, Phys. Rev. C 76, 065202 (2007) JPS meeting in Kyoto , Toshi Gogami

  6. JLab E05-115 experimental setup e + p → e’ + Λ + K+ 7Li , 9Be , 10B , 12C , 52Cr CH2, H2O Δp/p ~ 2×10-4 Solid angle ~ 7 [msr] θlab ~ 3 – 12 [deg] Δp/p ~ 2×10-4 Solid angle ~ 11 [msr] θlab ~ 2 – 12 [deg] JPS meeting in Kyoto , Toshi Gogami

  7. Polyethylene(CH2) target High intensity beam ~2.0 μA / (1×3 mm2)  Hydrogen was escaping from the target Before After JPS meeting in Kyoto , Toshi Gogami

  8. Λ, Σ0 from CH2 target Preliminary JPS meeting in Kyoto , Toshi Gogami

  9. Λ, Σ0 from CH2 target JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] p(e,e’K+)Λ ~1.8MeV (FWHM) Δm = 19 ± 17 keV/c2 Preliminary p(e,e’K+)Σ0 ~1.8MeV (FWHM) Δm = 73 ± 47 keV/c2 JPS meeting in Kyoto , Toshi Gogami

  10. Preliminary results of p(γ*,K+)Λ ( JLab E05-115 , Q2 ~ 0.01 [GeV/c]2 ) Preliminary JLab E05-115 (HES-HKS) 192±6±89 [ nb / sr ] 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) JPS meeting in Kyoto , Toshi Gogami

  11. Comparison with data of JLab Hall-A Large longitudinal term contributions? Preliminary p(γ*,K+)Λ ~ JLab E94-107 W ~ 2.2 GeV Q2 ~ 0.07 [GeV/c]2 p(γ*,K+)Λ ~ JLab E05-115 (HES-HKS) W ~ 1.9 GeV Q2 ~ 0.01 [GeV/c]2 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) JPS meeting in Kyoto , Toshi Gogami

  12. Summary • JLab E05-115 (HES-HKS) was performed in JLab Hall-C in 2009 • 7ΛHe,9ΛLi,10ΛBe,12ΛB, 52ΛCr, Λ, Σ0 • High statistical data of p(γ*,K+)Λ • cosθCM~0.97 , W ~1.9 GeV, Q2~0.01 [GeV/c]2 • 192±6±89 [ nb / sr] • Further studies • Mainz MAMI-C • Interference term (14aSC-2: 塚田) • JLab • New proposal JPS meeting in Kyoto , Toshi Gogami

  13. HES-HKS Collaborations JPS meeting in Kyoto , Toshi Gogami

  14. Thank you for your attention Prof. S.N.Nakamura Prof. O.Hashimoto End run party of E05-115 (Mar2010) JPS meeting in Kyoto , Toshi Gogami

  15. backup JPS meeting in Kyoto , Toshi Gogami

  16. Preliminary results of p(γ*,K+)Σ0 ( JLab E05-115 , Q2 ~ 0.01 [GeV/c]2 ) SAPHIR : K.H.Glander, Eur. Phys. J. A 19, 251-273 (2004) CLAS : R.Bradford, Phys. Rev. C 73, 035202 (2006) JLab E05-115 (HES-HKS) 62±6±26 [ nb / sr ] Preliminary JPS meeting in Kyoto , Toshi Gogami

  17. Detectors & Trigger HKS K+ p, π+ HES e- TOF walls (Plastic scintillators) • Cherenkov detectors • Aerogel (n=1.05) • Water (n=1.33) Drift chambers JPS meeting in Kyoto , Toshi Gogami

  18. Detectors & Trigger HKS K+ p, π+ HES e- TOF walls (Plastic scintillators) HES trigger (TOF1x2) ~2000 kHz HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz • Cherenkov detectors • Aerogel (n=1.05) • Water (n=1.33) Coincidence trigger HES x HKS < 2 kHz Drift chambers JPS meeting in Kyoto , Toshi Gogami

  19. Analysis process iteration HKS F2T function raw data decoding tracking x , x’ , y , y’ at Reference plane x’ , y’ , p at target particle ID (select K+) Missing mass F2T func. tune Energy calibration (p  Λ , Σ0) HES raw data decoding tracking x , x’ , y , y’ at Reference plane x’ , y’ , p at target F2T function JPS meeting in Kyoto , Toshi Gogami iteration

  20. Analysis process iteration HKS F2T function raw data decoding tracking x , x’ , y , y’ at Reference plane x’ , y’ , p at target particle ID (select K+) Missing mass F2T func. tune HES raw data decoding tracking x , x’ , y , y’ at Reference plane x’ , y’ , p at target F2T function JPS meeting in Kyoto , Toshi Gogami iteration

  21. HKS detectors June 2009 in JLab Hall-C 1 [m] • HKS trigger • CP = 1X ×1Y × 2X • K = WC ×AC •  CP × K − π+ K+ p ~18 [kHz] (8 [μA] on 52Cr) K+ p, π+ Drift chambers -KDC1,KDC2- • Cherenkov detectors -AC,WC- • Aerogel (n=1.05) • Water (n=1.33) TOF walls -2X,1Y,1X- (Plastic scintillators) σ ≈ 250 [μm] TOF σ ≈ 170 [ps] JPS meeting in Kyoto , Toshi Gogami

  22. HES Detectors HES D magnet Drift chambers - EDC1 , EDC2 - TOF walls - EH1 , EH2 - (Plastic scintillators) σ ~ 300 [ps] Time Of Flight HES trigger EH1 ×EH2 ~2 [MHz] (8 [μA] on 52Cr) e JPS meeting in Kyoto , Toshi Gogami

  23. Missing mass spectrum JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] Quasi free Λ from 12C p(e,e’K+)Λ ~1.8MeV (FWHM) Δm = 19 ± 17 keV/c2 p(e,e’K+)Σ0 ~1.8MeV (FWHM) Δm = 73 ± 47 keV/c2 Accidental Coincidence JPS meeting in Kyoto , Toshi Gogami

  24. e’ K+ e- JPS meeting in Kyoto , Toshi Gogami

  25. Considered efficiencies Simulation JPS meeting in Kyoto , Toshi Gogami

  26. P. Bydzovsky’s presentation at ECT* 2011 K+ production at small angles electroproduction SL: 0.41 = 0.35 + 0.004 - 0.001 + 0.06 ( e = 0.7 ) a steep Q2 dependence ? (g*,K+) JLab Hall-A E05-115 W=1.9 GeV Q2=0.01 (GeV/c)2 JPS meeting in Kyoto , Toshi Gogami

  27. Electro-production of K+Λ JLab E05-115 experiment by the (e,e’K+) reaction Small Q2 ( ~0.01 [GeV/c]2 )  almost real photon , JPS meeting in Kyoto , Toshi Gogami

  28. Estimation of the number of events by the fitting  ~Lambda~     Number : 6402.57     Mean   : 28.5527 +- 19.7152 [keV/c2]     ( Delta Mean : 28.5527 +- 19.7152 [keV/c2] )     Width  : 1937.59 +- 52.1221 [keV/c2]  ~Sigma~     Number : 1688.07     Mean   : 76809.3 +- 42.7735 [keV/c2]     ( Delta Mean : -149.659 +- 42.7735 [keV/c2] )     Width  : 1848.15 +- 121.343 [keV/c2] Fitting function : B : Half width at half maximum C : Center value peak background JPS meeting in Kyoto , Toshi Gogami

  29. Cut conditions to make the missing mass • Cut conditions • 1.0 > NWC1+2 • 5.0 < AC1+2+3 • -1.0 < coincidence time + 54.9 < 1.0 • 0.08 < Mass square < 0.44 • HKS tracking chi-square < 150.0 • HES tracking chi-square < 150.0 JPS meeting in Kyoto , Toshi Gogami

  30. K+ survival Ratio after the mass square cut (CH2) K+ survival ratio If applied these two cut at the same time (Suv. Ratio)total = (Suv. Ratio1) + (Suv. Ratio2) – 1.0 Suv. ratio1 Suv. ratio2 Cut 2 Cut 1 JPS meeting in Kyoto , Toshi Gogami

  31. K+ survival ratio after AC cut (CH2) looser cut of AC NPE (accut,wccut) = (5,-0.1)pi suv. ratio: 0.0631439+-0.00148976K  suv. ratio: 0.876875+-0.00513167p  suv. ratio: 0.911427+-0.0023794(accut,wccut) = (10,-0.1)pi suv. ratio: 0.105762+-0.0019663K  suv. ratio: 0.931211+-0.00536427p  suv. ratio: 0.94023+-0.00243485(accut,wccut) = (15,-0.1)pi suv. ratio: 0.141455+-0.00231043K  suv. ratio: 0.956913+-0.00547386p  suv. ratio: 0.960014+-0.00247285 p K+ π+ Stricter cut of AC NPE p K+ π+ JPS meeting in Kyoto , Toshi Gogami

  32. K+ survival ratio after WC cut (CH2) looser cut of WC NPE (accut,wccut) = (2000,1.1)pi suv. ratio: 0.922368+-0.00752531K  suv. ratio: 0.987653+-0.00566791p  suv. ratio: 0.133889+-0.000701787(accut,wccut) = (2000,1)pi suv. ratio: 0.963952+-0.00777583K  suv. ratio: 0.989093+-0.0056741p  suv. ratio: 0.176933+-0.000821917(accut,wccut) = (2000,0.9)pi suv. ratio: 0.971601+-0.00782181K  suv. ratio: 0.999575+-0.00571909p  suv. ratio: 0.259314+-0.00102927 p K+ π+ Stricter cut of WC NPE K+ p π+ JPS meeting in Kyoto , Toshi Gogami

  33. Tracking efficiencies • ~~~~ HKS~~~~~~~ch2 : Tracking Efficiency : 0.998974 +- 0.00760814 (0.761596%)h2o : Tracking Efficiency : 0.961109 +- 0.00190445 (0.198152%)li : Tracking Efficiency : 0.996378 +- 0.0205954 (2.06703%)be : Tracking Efficiency : 0.995274 +- 0.00535923 (0.538468%)b : Tracking Efficiency : 0.99921 +- 0.00912634 (0.913356%)c : Tracking Efficiency : 0.987929 +- 0.00179032 (0.181219%)cr1 : Tracking Efficiency : 0.974892 +- 0.00304261 (0.312097%)cr2 : Tracking Efficiency : 0.965851 +- 0.00320905 (0.332251% ) • ~~~~ HES~~~~~~~ch2 : Tracking Efficiency : 1 +- 0.00527844 (0.527844%)h2o : Tracking Efficiency : 1 +- 0.00095474 (0.095474%)li : Tracking Efficiency : 1 +- 0.0172701 (1.72701%)be : Tracking Efficiency : 1 +- 0.00419163 (0.419163%)b : Tracking Efficiency : 1 +- 0.00820523 (0.820523%)c : Tracking Efficiency : 1 +- 0.00153384 (0.153384%)cr1 : Tracking Efficiency : 1 +- 0.00100727 (0.100727%)cr2 : Tracking Efficiency : 1 +- 0.00103985 (0.103985%) 1 ….!? Need to check tracking code JPS meeting in Kyoto , Toshi Gogami

  34. HKS efficiency • εHKS = 0.169 • AC : 0.877 (+-0.005) • WC : 0.990 (+-0.006) • Tracking : 0.999 (+0.001, - 0.007) • M2 : 0.96 • Ctime : 0.99 • fdecay : 0.252 (± 0.006) • fburn : 0.82 JPS meeting in Kyoto , Toshi Gogami

  35. Definition of the cross section εcommon ~ 0.97 -5 SIMULATION JPS meeting in Kyoto , Toshi Gogami

  36. Theta and Momenta of the scattered electrons JPS meeting in Kyoto , Toshi Gogami

  37. Angular acceptance cut θe’ > 0.05 rad JPS meeting in Kyoto , Toshi Gogami

  38. JPS meeting in Kyoto , Toshi Gogami

  39. Back ground estimation Optimal scaling factor  1.08 Scaling factor : 1. Black + (Green × scaling factor) = Blue JPS meeting in Kyoto , Toshi Gogami

  40. Current missing mass spectrum JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] JPS meeting in Kyoto , Toshi Gogami

  41. Current missing mass spectrum JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] Quasi free Λ from 12C Accidental Coincidence JPS meeting in Kyoto , Toshi Gogami

  42. The number of events of Λ and Σ0 JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] Λ Σ0 5760± 125 (Integrated : -5 – 9 MeV/c2) 1579± 94 (Integrated : 72 – 86 MeV/c2) JPS meeting in Kyoto , Toshi Gogami

  43. Momentum acceptance cut (Σ0) ~8.5 msr HES momentum region • 0.770 – 0.900 • 0.770 – 0.835 • 0.835 – 0.900 52ΛV g.s. JPS meeting in Kyoto , Toshi Gogami

  44. Momentum acceptance cut (Λ) ~8.5 msr HES momentum region • 0.770 – 0.900 • 0.770 – 0.835 • 0.835 – 0.900 52ΛV g.s. JPS meeting in Kyoto , Toshi Gogami

  45. Momentum acceptance cut ~8.5 msr HES momentum region • 0.770 – 0.900 GeV/c • 0.770 – 0.835 GeV/c • 0.835 – 0.900 GeV/c Λ Σ0 JPS meeting in Kyoto , Toshi Gogami

  46. Momentum acceptance cut ~8.5 msr HES momentum region [ GeV/c ] 0.790 ~ 0.844 ( 1.922 < W [ GeV ] < 1.947 ) Λ Σ0 JPS meeting in Kyoto , Toshi Gogami

  47. Data Summary JLab E05-115 (2009/June – 2009/Nov) JPS meeting in Kyoto , Toshi Gogami

  48. Singles rate summary HKS Up to ~30 [MHz] HKS trigger ~ 10[kHz] HES Up to ~15 [MHz] COIN 2.0 [kHz] HES trigger ~ a few[MHz] JPS meeting in Kyoto , Toshi Gogami

  49. Hit wires event display (2) KDC1 KDC2 v v’ v v’ uu’ uu’ • GREEN regionSelective region • RED markers & linesSelected hit wires • BLACK markers & lines Rejected hit wires particle particle x x’ x x’ JPS meeting in Kyoto , Toshi Gogami

  50. KTOF multiplicity ~2.7 ~1.8 ~6.5 ~3.8 Multiplicity of KDC are not only high but also TOF counters are! (for heavy target ) CH2 , 76314 52Cr , 77124 JPS meeting in Kyoto , Toshi Gogami

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