1 / 98

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.

shayna
Download Presentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related