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Study of light hypernuclei by the (e,e’K + ) reaction

Study of light hypernuclei by the (e,e’K + ) reaction. Graduate school of science, Tohoku Univ. Toshiyuki Gogami. JLab E05-115 collaboration, 2009, JLab Hall-C. Contents. (e,e’K + ) spectroscopic experiment in JLab 7 Λ He, 9 Λ Li, 10 Λ Be, 16 Λ N, 12 Λ B, 28 Λ Al, 52 Λ V

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Study of light hypernuclei by the (e,e’K + ) reaction

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  1. Study of light hypernuclei by the (e,e’K+) reaction Graduate school of science, Tohoku Univ. Toshiyuki Gogami JLab E05-115 collaboration, 2009, JLab Hall-C

  2. Contents • (e,e’K+) spectroscopic experiment in JLab • 7ΛHe,9ΛLi,10ΛBe, 16ΛN, 12ΛB, 28ΛAl,52ΛV • Precision light Λ hypernuclear spectroscopy • 7ΛHe (preliminary result) ΛN charge symmetry breaking APFB2011 in Korea (T.Gogami)

  3. Λhypernuclear spectroscopy 52LV Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564.

  4. 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 • Large Momentum transfer • Λ can be bounded in deeper orbit • Λ’s spin at forward angle • Spin flip ~ spin non-flip • Proton  Λ • Absolute mass value calibration APFB2011 in Korea (T.Gogami)

  5. JLab E05-115 experimental setup e + p → e’ + Λ + K+ 7Li , 9Be , 10B , 12C , 52Cr 2×10-4 7 [msr] 3 – 12 [deg] 2×10-4 8.5 [msr] 2 – 12 [deg] • (e,e’K+) experiment • Coincidence experiment (K+ and e-) • Small cross section ( ~100 [nb/sr] ) 1/1000 • Energy resolution Sub MeV (FWHM) • Primary beam • High intensity • Thin target (~100 [mg/cm2]) • High quality APFB2011 in Korea (T.Gogami)

  6. JLab CEBAF ( Continuance Electron Beam Accelerator Facility ) • Requirements for accelerator • High duty factor (~100%) • High intensity ( >a few 10 μA ) • Smallemittance ( ~2 [mm・μrad] ) • Small ΔE/E ( <1×10-4 ) • (e,e’K+) experiment • Coincidence experiment (K+ and e-) • Small cross section ( ~100 [nb/sr] ) 1/1000 • Energy resolution sub MeV (FWHM) 100 [m] CEBAF was unique facility before MAMI updated Experimental Hall APFB2011 in Korea (T.Gogami)

  7. (e,e’K+) experiment in JLab Proof of feasibility 2000 1st generation exp.JLab E89-009 e’-spectrometer + K+-spectrometer 12ΛB ~ 750 [keV] (FWHM) 2004 JLab E94-107 (K+, e+)-spectrometers + septum 9ΛLi,12ΛB,16ΛN ~ 670 [keV] (FWHM) Hall-C Establish exp. method 2005 2nd generation exp.JLab E01-011 e’-spec. Optimized configuration + HKS(K+) 7ΛHe,12ΛB,28ΛAl ~ 600 [keV] (FWHM) Final analysis stage Hall-A Hall-C Up to Medium heavy 2009 3rd generation exp.JLab E05-115 HES(e’) Optimized configuration + HKS(K+) 7ΛHe,9ΛLi,10ΛBe,12ΛB,52ΛV ≤ 500 [keV] (FWHM) Analyzing Avoid huge background at very forward angle Hall-C APFB2011 in Korea (T.Gogami)

  8. Analysis status of E05-115 JLab E05-115 p(e,e’K+)Λ,Σ0 ~40 hours (5 shifts) • p(e,e’K+)Λ,Σ0  HES-HKS basic system works well Very preliminary • Analysis is in progress • Energy (mass) calibration • Developing new code for high multiplicity data Λ and Σ0 can be seen at the same time Up to Medium heavy 2009 3rd generation exp.JLab E05-115 HES(e’) Optimized configuration + HKS(K+) 7ΛHe,9ΛLi,10ΛBe,12ΛB,52ΛV ≤ 500 [keV] (FWHM) E.M background ∝ ~Z2 Hall-C APFB2011 in Korea (T.Gogami)

  9. -6.650.030.2 MeV from α L n n Experimental data of A=7 system Four-body cluster model for T=1 iso-triplet hypernuclei (E.Hiyama et al., PRC 80, 2009) α+ Λ + N + N Old 7ΛHedata ( M.Juric, NPB 52, 1973 ) JLab E01-011 7Li(e,e’K+)7ΛHe -BL [MeV] Preliminary Compare to theoretical calculation APFB2011 in Korea (T.Gogami)

  10. -6.650.030.2 MeV from α L n n Theoretical calculation of A=7 system Four-body cluster model for T=1 iso-triplet hypernuclei (E.Hiyama et al., PRC 80, 2009) α+ Λ + N + N Old 7ΛHedata ( M.Juric, NPB 52, 1973 ) JLab E01-011 7Li(e,e’K+)7ΛHe -BL [MeV] Preliminary Compare to theoretical calculation APFB2011 in Korea (T.Gogami)

  11. Theoretical calculation of A=7 system -6.650.030.2 MeV from α L n n Four-body cluster model for T=1 iso-triplet hypernuclei (E.Hiyama et al., PRC 80, 2009) α+ Λ + N + N JLab E01-011 7Li(e,e’K+)7ΛHe Preliminary -BL (MeV) CSB interaction is determined to reproduce BΛ of 4ΛH and 4ΛHe. -5.41 Decay pion spectroscopy Will be talked by E.Hiyama in Plenary 6 session(8/24) APFB2011 in Korea (T.Gogami)

  12. Summary • (e,e’K+) spectroscopic exp. in JLab • E89-009 (2000,Hall-C) 12ΛB • E94-107 (2004,Hall-A) 9ΛLi,12ΛB,16ΛN • E01-011 (2005,Hall-C) 7ΛHe,12ΛB,28ΛAl • E05-115 (2009,Hall-C) 7ΛHe,9ΛLi,10ΛBe, 12ΛB,52ΛV • Precision light Λ hypernuclear spectroscopy • 7ΛHe (preliminary result by E01-011) • 10ΛBe (analyzing) Final analysis stage Analysis stage ΛN charge symmetry breaking APFB2011 in Korea (T.Gogami)

  13. EndThank you very much APFB2011 in Korea (T.Gogami)

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