1 / 56

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

bertha-reid
Download Presentation

Medium heavy hypernuclear spectroscopic experiment JLab E05-115

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. 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)

More Related