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Recent Spectroscopic Investigation of P-Shell Λ - hypernuclei by the (e, eK+) Reaction - Analysis Status of E05115 - Chunhua Chen Hampton University July.

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Presentation on theme: "Recent Spectroscopic Investigation of P-Shell Λ - hypernuclei by the (e, eK+) Reaction - Analysis Status of E05115 - Chunhua Chen Hampton University July."— Presentation transcript:

1 Recent Spectroscopic Investigation of P-Shell Λ - hypernuclei by the (e, eK+) Reaction - Analysis Status of E Chunhua Chen Hampton University July 18,2012 The fourth workshop on hadron physics in China and Opportunities in USA

2 Introduction Merits of (e,eK + ) experiment: Large momentum transfer Excitation of deeply-bound state p to conversion Mirror or Neutron-rich hypernuclei Production of both spin-flip/non-flip states; High resolution because of the quality of the CEBAF beam Merits of (e,eK + ) experiment: Large momentum transfer Excitation of deeply-bound state p to conversion Mirror or Neutron-rich hypernuclei Production of both spin-flip/non-flip states; High resolution because of the quality of the CEBAF beam Experimental Goals: Spectroscopy of Medium - heavy hypernucleus 52 Cr(e,eK+) 52 V Spectroscopy of Light hypernuclei- p shell hypernuclei 12 C(e,e'K+) 12 Λ B, 7 Li(e,e'K+) 7 Λ He, 10 B(e,e'K+) 10 Λ Be, and 9 Be(e'K+) 9 Λ Li Calibration by the elementary process p(e,eK + ) or : H 2 O and CH 2 Results are important in determining, S N and V 0 terms from s states and S term from states with at higher orbits Dr. Tangs Talk E05115 The 3 rd generation spectroscopic investigation of Lambda hypernuclei by the Reaction (e,eK + ) at Jlab Hall C

3 Experimental Setup Splitter Magnet HKS HES Bremsstralung flux Virtual photon flux factor K+K+ e e

4 PreChicane-SPL-(HKS+HES) Configuration

5 Kinematics of the E Experiment p K + Momentum: 2.344GeV/c Momentum: 0.844GeV/c ±17% Angular acceptance: 3° 9° Momentum: 1.2GeV/c ±12.5% Angular acceptance : 1° 13 ° 1.5GeV γ* Scattered electron K+K+ Electron beam Target nucleus p Coincidence measurement

6 Experimental Setup -Detector Package- HES-D e EHOD2 EHOD 1 EDC2 EDC1 HES Detectors

7 Analysis Flow Chart Tracking (KDC) TOF (Hodoscopes) KID (AC,WC,LC) HKS Focal Plane (X,X,Y,Y,T fp ) HKS Optics (HKS+Splitter) HKS Target Plane (X, Y, P, T tar ) Tracking (EDC) TOF (Hodoscopes) HES Focal Plane (X,X,Y,Y, T fp ) HES Optics (HES+Splitter) HES Target Plane (X, Y, P, T tar ) Coincident (RF ) Kinematics Correction (Beam, Target effects, Momentum, Angular) Missing Mass Raw Data Need to do Data & Info Lambda&Sigma 12 Λ Bgs Spectra Geant4 Simulation HKS Sieve Slit HES Sieve Slit

8 Calibration Procedure of the Spectrometer System Forward Tuning Backward tuning mass spectroscopy Nonlinear Least Chi 2 fitting Kinematical scan Initial state Magnetic field study Geant4 Simulation Focal plane pattern Real Data Λ & Σ mass spectroscopy Field map Focal plane pattern Matching level A SS pattern SS hole Matching level B Kinematical parameters Independent level C matrices A&B&C

9 Forward Optics Tuning Purple: Real HKS SS data Blue: Geant4 Simulation Splitter field contour on xoz plane The leakage of splitter fringe field causes the cross talk between the splitter and quadrupoles Purple: Geant4 simulation green: Real HES SS data Target BeamKaon Q1 Q2

10 Forward Optics Tuning The asymmetry functions are introduced and tuned for HKS&HES quadruple field Bx and By, independently.

11 The Mass Status of Forward Optics Tuning Start Point after forward tuning 11

12 Backward Spectrometer System Calibration Spectrometer system calibration key to reach 400 keV energy resolution Common splitter : Separated single arm kinematics and optics calibration is not possible Technique: 2-arm coupled calibration for both kinematics and optics Using known masses of, from CH2 target and identified known hypernuclear bound states 12 Bgs for spectrometer calibration HES spectrometer system Beam Target Splitter HKS HES Sieve Slit To beam dump 12 B (gs) Kaon Momentum (MeV/c) Kinematics coverage Sieve Slit

13 Mathematical optimization by Nonlinear Least Chi 2 fitting a.Central kinematics scan (m Λ,m Σ,Δm ΛΣ ) b.Angular matrices (m Λ,m Σ,σ) c.Momentum matrices ( 12 Λ Bgs) d.Iteration

14 Preliminary status Allowing precise calibration of mass scale

15 Preliminary status – 12 Λ B E in Hall A (2003 & 04) Phase II in Hall C (E ) ~500 keV FWHM HKS in B (E05-115)

16 Preliminary status – 10 Λ Be αα n Λ αα p Λ 10 Be Λ 10 B Λ -8.38MeV Cal: 8.84 MeV (without CSB) Cal: 8.76 MeV (with CSB) 9 Be+Λ 0 MeV By E. Hiyama Preliminary

17 Preliminary Result - 7 Λ He E01011 data E. Hiyama, et al., PRC (1996) n n 6 He core 3/2 + &5/2 + Preliminary E05115

18 Preliminary status – 9 Λ Li B = (emulsion, average over only 8 events) s s s Sotona and Millener Saclay-Lyon model for elementary process s Ex: 0.0 ~0.84 ~1.90 ~ 2.75 ~3.77 ~4.38 Hall C HKS E B =

19 Summary and to do By current calibration method, we are able to get clear mass spectroscopy, which is not included in the calibration data set; Current resolution is still factor of 2 away from expected resolution, the iteration will continue to improve the optical matrices as well as the kinematics; Other issue: High multiplicity tracking problem for heavy target data, Japanese people are still working for it. 19

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21 Back Up

22 Particle ID

23 Experimental Setup - Tilt Method- Electroproduction differential cross section(Miloslav Sontana) Г : virtual photon flux

24 7 Li target : Physics of (A = 7,T=1) E. Hiyama et al. PRC80,054321(2009) (EXP) (EXP) Possible Charge Sym. Breaking? NO Reliable DATA (T=1) B Λ = Li 7 He 7 Be α Λ n n α Λ n p α Λ p p M.Jurič et al., NP B52(1973) 1

25 7 He α n n Λ α Unbound neutron halo Bound states Direct Observation of s glue-like role n n NO DATA Another Physics of HKS-HES (E05-115)

26 10 B target Milleners parameterization(V,D,S N,S,T) Hyperballs data αα n Λ 10 Be Λ αα p Λ 10 B Λ Imperfect treatment of Tensor force? Bad wavefunction of the core nucleus? predicts >200keV separation 10 B(e,eK) Cluster Calc. based on the same framework

27 Coincident Time: The correlation of HKS target time and HES target time, give us the coincident spectrum: Real events Accidental PID cut is applied and path length correction has been done Coincident Trigger Set HES: HES trigger =(EHODO1)×(EHODO2) ×:AND


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