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Medium heavy hypernuclear spectroscopic experiment JLab E05-115

Medium heavy hypernuclear spectroscopic experiment JLab E05-115. Tohoku Univ. Toshiyuki Gogami. June2009 @ JLab Hall-C. Contents. Introduction for E05-115 E05-115 setup Analysis status. Introduction for E05-115 (e,e’K + ) reaction experiment Experimental motivation JLab E05-115 setup

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Medium heavy hypernuclear spectroscopic experiment JLab E05-115

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  1. Medium heavy hypernuclear spectroscopic experiment JLab E05-115 Tohoku Univ. ToshiyukiGogami June2009 @ JLab Hall-C 22nd Indian-summer school (SNP2010)

  2. Contents • Introduction for E05-115 • E05-115 setup • Analysis status 22nd Indian-summer school (SNP2010)

  3. Introduction for E05-115 • (e,e’K+) reaction experiment • Experimental motivation • JLab • E05-115 setup • Analysis status 22nd Indian-summer school (SNP2010)

  4. Spectroscopic experiment via (e,e’K+) reaction e + p e’ + K+ + Λ Feynman diagram e- e e u u γ* K+ – γ* u s p d s p K+ u Λ Λ d n target nucleus measure Missing mass : M2HY = (Ee + MT - EK+ - Ee’)2 - ( pe - pK+- pe’)2 • Binding energy • Cross section 22nd Indian-summer school (SNP2010)

  5. (e,e’K+) reaction (e,e’K+) (π+ , K+) (K- , π-) e + p e + K+ + Λ π+ + n K+ + Λ K- + n π- + Λ e e – – u u u u Reaction K+ π+ – – K- π- s s d u d u γ* K+ – u s p d s d s d s n d d n d d u Λ Λ Λ u u u u d Momentum transfer (pbeam = 1.5 [GeV/c] ) ~300 [MeV/c] ~300 [MeV/c] ~90 [MeV/c] Λ can be bounded in deeper orbit flip ≈non-flip non-flip non-flip Λ’s Spin Spin dependent structure proton neutron neutron Λ’s from Mirror lambda hypernuclei primary secondary secondary Beam High quality , high intensity Target Thin (~100 mg/cm2) (Isotopically enriched) Thick(> a few [g/cm2] ) Thick(> a few [g/cm2] ) Energy resolution (FWHM) ≤ 500 [keV] 1 – 3 [MeV] 1 – 3 [MeV] Fine structure

  6. E05-115 experimental motivation (1) • 2009 Aug – Nov @ JLab Hall-C • (e,e’K+) reaction • Target : 7Li , 9Be , 10B , 12C , 52Cr First try It is difficult experimentally. “ b.g. electron due to brems. ∝ ~Z2 “ • p-shell(7He,9Li,10Be,12B) • Charge symmetry breaking • Λ-Σ coupling Λ Λ Λ Λ • Medium heavy (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] A = 52

  7. E05-115 experimental motivation(2) 1f7/2 FULL(8) f 7+ 6+ or 1d3/2 FULL(4) FULL(4) 6- 5- d ls splitting information can be extracted or ・ ・ ・ ・ ・ ・ 5+ 4+ p ls splitting ∝ 2l+1 or n = 28 p = 24 4- 3- s or 52Cr Λ 52ΛV d p f s Photo- and electro production of medium mass Λ-hypernuclei ,P.Bydzovsky et al. (2008) 22nd Indian-summer school (SNP2010)

  8. JLab CEBAF ( Continuance Electron Beam Accelerator Facility ) • Requirement for accelerator • high duty factor • high intensity • smallemittance • small ΔE/E • E05-115 experiment • coincidence experiment (K+ and e-) • small cross section ( ~100 [nb/sr] ) • energy resolution < 500 [keV] (FWHM) CEBAF can satisfy these requirements Thomas Jefferson National Accelerator Facility 22nd Indian-summer school (SNP2010) 100 [m]

  9. Introduction for E05-115 • E05-115 setup • setup • HES detectors • HKS detectors • Analysis status 22nd Indian-summer school (SNP2010)

  10. E05-115 Setup e + p  e’ + K+ + Λ Splitter magnet Δp/p = 2×10-4 Solid angle = 7 [msr] θe = 3° – 14.5° Δp/p = 2×10-4 Solid angle = 8.5 [msr] θK+ = 1° – 14° pre chicane 22nd Indian-summer school (SNP2010)

  11. HESdetectors Reference plane hit pattern HES trigger EH1 ×EH2 ~2 [MHz] (8 [μA] on 52Cr) • HES detectors • Drift chamber : EDC1 , EDC2 • Scintillator wall : EH1 ,EH2 Tracking e’ Trigger Picture from downstream view

  12. HKS detectors • HKS trigger • CP = 1X ×1Y × 2X • K = WC ×AC •  CP × K − ~18 [kHz] (8 [μA] on 52Cr) main background π+ , p π+ K+ • HKS detectors • Drift chamber : KDC1 , KDC2 • Scintillator wall : KTOF1X ,2X,1Y • Cherenkov detector : Aerogel , Water , Lucite p Tracking Trigger , TOF PID 22nd Indian-summer school (SNP2010)

  13. Introduction for E05-115 • E05-115 setup • Analysis status • data summary • analysis process • tracking efficiency 22nd Indian-summer school (SNP2010)

  14. E05-115 ( 2009 Aug – Nov ) Data summary Physics Data Λ Λ Λ Λ (@36μA) Λ Calibration Data 22nd Indian-summer school (SNP2010)

  15. 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+) E05-115 450.8 [mg/cm2] 2.0 [μA] 38 [hours] σ = 2 [MeV/c2] (NOT TUNED) Missing mass p(e,e’K+)Λ p(e,e’K+)Σ0 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 22nd Indian-summer school (SNP2010) iteration

  16. Multiplicity in chambers • Current tracking code • is created for low multiplicity data • This experiment • Multi-hit TDC • Heavier target (52Cr) • High multiplicity Drift chamber E01-011 at JLab Hall-C (Heaviest target : 28Al) 52Cr target mean ~ 6 hit tracking efficiency ↓ 0 20 22nd Indian-summer school (SNP2010) Multiplicity of typical layer

  17. Tracking efficiency KTOF1X Input tracks in simulation (we know everything about these tracks) data file (hit wire information) real analyzer K+ KDC2 KDC1 CH2 target Current analyzer cannot handle with high multiplicity data 52Cr target Need to improve tracking code Now developing 22nd Indian-summer school (SNP2010)

  18. Summary • E05-115 experiment • 2009 Aug – Nov @JLab Hall C • 7He,9Li,10Be,12B,52V • Spectrometers and Detectors work well • Tracking code • developing new tracking code for high multiplicity first try to measure Λ-hypernuclei up to A=52 via (e,e’K+) Λ Λ Λ Λ Λ E05-115 450.8 [mg/cm2] 2.0 [μA] 38 [hours] σ = 2 [MeV/c2] (NOT TUNED) Preliminary • optimize parameters • ( time, position , cut ) • debug 22nd Indian-summer school (SNP2010)

  19. End.Thank you S.N.Nakamura O.Hashimoto End run party of E05-115 on Mar2010 22nd Indian-summer school (SNP2010)

  20. backup 22nd Indian-summer school (SNP2010)

  21. Multiplicity in chambers Multi-hit TDC HES layer 10 6 52Cr target CH2 target mean ~ 1 hit mean ~ 1 hit HKS 6 6 layer 52Cr target CH2 target mean ~ 6 hit mean ~ 2 hit 22nd Indian-summer school (SNP2010)

  22. Multi-hit TDC Origin of multiplicity e,+e- e+ Fringeof hall prove ∝ Z2 x’ [rad] x [cm]

  23. E05-115 experiment motivation • 2009 Aug – Nov @ JLab Hall-C • (e,e’K+) reaction • Target : 7Li , 9Be , 10B , 12C , 52Cr • p-shell(7He,9Li,10Be,12B) • charge symmetry breaking • Λ-Σ coupling • Medium heavy (52V) • s-,p-,d-orbit binding energy & cross section • Mass dependence of Λ single particle energy • l・s splitting　∝ 2l+1 • 絵 • charge symmetry • Λ-Σ coupling 22nd Indian-summer school (SNP2010)

  24. Λand Σ0 mass spectrum Fitting Integral the function Number of event Cross section FWHM ~ 4.7 [MeV/c2] with not tuned F2T function 22nd Indian-summer school (SNP2010)

  25. HES Tilt method Main background source for electron arm • bremsstrahlung • Møller Angular dependence of electrons (Simulation) HES was tilted to avoid huge background at forward 22nd Indian-summer school (SNP2010) Tilt method

  26. HES detectors resolution EDC1 EHODO1 counter ID σ = 250 [μm] EHODO1 to EHODO2 TOFresolutionσ = 360 [ps] TOF [ns] EDC2 σ = 170 [μm] TOF [ns] Momentum resolution (~2×10-4) Enough resolution (but can be improved)

  27. (e,e’K+)reaction elementary step e+p --> e’+Λ+K+ • physical advantage • large momentum transfer deeply bound • Spin-flip andSpin non-flip • p  Λ • experimental advantage • high quality primary beam • high intensity beam thin target energy resolutiongood Bothe’ and K+ have forward peak  need to be detected at forward

  28. E05-115 spec 22nd Indian-summer school (SNP2010)

  29. 12C E89-009 (2000) E01-011 (2005) 28Si 52Cr E05-115 (2009) Z 6 13 24 difficult (brems. increase with ~Z2 ) 22nd Indian-summer school (SNP2010)

  30. Λ hypernuclei experiment via (e,e’K+) reaction at JLab Hall-C Aug - Nov luminosity ×137 1/200

  31. E05-115 experimental motivation • 2009 Aug – Nov @ JLab Hall-C • (e,e’K+) reaction • Target : 7Li , 9Be , 10B , 12C , 52Cr Λ Λ Λ Λ first time • p-shell(7He,9Li,10Be,12B) • charge symmetry breaking • Λ-Σ coupling Λ 1f7/2 • Medium heavy (52V) • s-,p-,d-orbit binding energy • & cross section • Mass dependence of Λ single particle energy • l・s splitting　∝ 2l+1 Λ FULL(8) f 7+ 6+ 1d3/2 FULL(4) FULL(4) d 6- 5- ・ ・ ・ ・ ・ ・ p 5+ 4+ n = 28 p = 24 s 4- 3- d p f s Photo- and electro production of medium mass Λ-hypernuclei ,P.Bydzovsky et al. (2008) 22nd Indian-summer school (SNP2010)

  32. Medium heavy hypernuclei experiment motivation 3rd generation E05-115 (2009) 2nd generation E01-011 (2005) 1st generation E89-009 (2000) precision measurement of medium heavy hypernuclei 52Cr(e,e’K+)52ΛV • s-,p-,d-orbit binding energy & cross section • Mass dependence of Λ single particle energy • l・s splitting∝ 2l+1

  33. E05-115exp. schematic diagram Λ hypernuclei experiment via (e,e’K+) +Tilt method e + p  e’ + Λ + K+ e + p  e’ + Σ0+ K+ target nucleus beam 2 [ μA ] Missing mass measure given can be derived

  34. Optimization tilt angle by Simulation • Figure of Merit (FoM) • rate of electrons associated with hypernucleiS • rate of electronsfrom Møller scattering NMφller • rate of electrons from bremsstrahlungNBrems 6.5o

  35. Coincidence time Tcoin Λ+ accidental event K+同定後 coincidence time Accidental Accidental Coincidence time [ns] accidental event 2 [ns] beam bunch structure

  36. Typical rate for each target

  37. beam momentum and recoil momentum

  38. VP and brems. flux Ei=2.344[GeV],ω=1.5[GeV]

  39. central momentum • P(γ,K+)Λで生成断面積が最も大きくなるのは仮想光子のエネルギーω=1.5[GeV]のときである。ω=1.5[GeV]とする為には、 Ee’=Ee-ω =2.344-1.5 =0.844[GeV] この散乱電子のエネルギー領域では、 E2e’=m2e’+p2e’~= p2e’ とみなすことができる。 この為、HESの中心運動量は0.844[GeV/c]をとることにした。

  40. Trigger i:Group ID ×:AND ＋:OR • HKSside • TOF trigger (CP)i=(KTOF1X)i×(KTOF1Y)×(KTOF2X)i • WCand AC veto trigger (K)i=(WC)i×(AC)i • (CP)iand (K)i coincidence trigger (HKS)i=(CP)i×(K)i • HKSトリガー HKStrigger=Σ(HKS)i • (WC)i=(WC1)i×(WC2)i • (AC)i=2/3{(AC1)i×(AC2)i×(AC3)i} • (AC1)i=(AC1)iTOP+(AC1)iBOT • (AC2)i=(AC2)iTOP+(AC2)iBOT • (AC3)i=(AC3)iTOP+(AC3)iBOT • HESside • HEStrigger=(EHODO1)×(EHODO2) • coincidence trigger • COINtrigger=(HKStrigger)×(HEStrigger)

  41. Number of photon aerogel water lucite 22nd Indian-summer school (SNP2010)

  42. Normalized NPE (hwatnkn1,2) 2 type of WC need two cuts • easier to select K+ than before

  43. Yield estimation with simulation beam intensity: 30 [μA] target thickness: 100[mg/cm2] cross section : 100[nb/sr] ≈ expected value from real QF data  30 [/hour] ×3~4 real data

  44. Angler acceptance 2nd generation exp. E01-011 incident beam energy 1.851 2.344 [GeV] background gather to forward accept more forward angle • HEShas large angler acceptance yield UP 3rd generation exp.E05-115

  45. Solid angle &Momentum matching ~ 7.5 [msr] HKS ~ 5.0 [msr] 52ΛV g.s. HES 22nd Indian-summer school (SNP2010)

  46. HESdetectors Reference plane hit pattern HES trigger EH1 ×EH2 ~2.0 [MHz] (8.0 [μA] on 52Cr) σ = 250 [μm] Tracking σ = 170 [μm] e’ Trigger σ = 350 [ps] Time correction Picture from downstream view

  47. HKS detectors • HKS trigger • CP = 1X ×1Y × 2X • K = WC ×AC • CP × K main background π+ , p ~18.0[kHz] (8 [μA] on 52Cr) σ = 170 [μm] Tracking β π+ TOF σ = 0.03 K+ WC NPE 1 + 2 Particle ID p β (resolution σ = 0.03) 22nd Indian-summer school (SNP2010)

  48. E05-115 ( 2009 Aug – Nov ) Data summary Physics Data Λ Λ Λ Λ Λ Calibration Data measured assumption 22nd Indian-summer school (SNP2010)

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