E01-011 & E05-115: Hypernuclear spectroscopy

1. E01-011 & E05-115: Hypernuclear spectroscopy S.N.Nakamura, Tohoku Univ. JLab HallC Meeting 22/Jan/2010, JLab

2. The AZ(e,e’K+) AL(Z-1)reaction for hypernuclear spectroscopy AZ AL(Z-1) p

3. E94-107 9Be 12C 16O E01-011 7Li 12C 28Si Hypernuclei in wide mass range 1 E89-009 12C 20 50 200 1057 A Elementary Process • Neutron/Hyperon star, Strangeness matter • Neutron/Hyperon star Strangeness electro-production Light Hypernuclei (s,p shell) • Hyperonization  • Softening of EOS ? • Superfluidity • Fine structure • Baryon-baryon interaction in SU(3) • LS coupling in large isospin hypernuclei • Cluster structure • Medium - Heavy hypernuclei • Single-particle potential • Distinguishability of a L hyperon • U0(r), mL*(r), VLNN, ... Shell model Few body calc. Bare LN Int. Mean Field Theory Cluster calc.

4. 12C (e,e’K) 12B Calibration and Reference spectrum s(2-/1-) gs resolution: 465 keV (FWHM) JLAB – HKS Preliminary p C.E. #1 (1-) Count s / 0.15 MeV C.E. #2(2-/1-) JLab E94-107 (2004) Hall A FWHM~670keV 12B Accidentals Counts /0.2 MeV B (MeV) 12C (p,K) 12C KEK E369 (2001) FWHM~1.5 MeV Excitation Energy(MeV)

5. p n n n Λ Λ p Λ p α α α 7Li target :Physics of (A = 7,T=1) E. Hiyamaet al. PRC80,054321(2009) M.Jurič et al., NP B52(1973) 1 7LBe -3.79 (EXP) BΛ=-5.58 7LLi -4.42 Possible Charge Sym. Breaking? -5.40 (EXP) -5.40 NO Reliable DATA -6.39 7LHe (T=1)

6. 7Li(e,e’K+)7LHe Preliminary result #1 Theoretical calculation Binding energy: Hiyama w/o CSB Cross section: Sotona et.al. (1.3 < Eg < 1.6 GeV, 1 < qK < 13 deg.) Resolution : ~510 keV (FWHM) for g.s. Data taking : ~30 hours w/ 30 mA

7. 7Li target :Physics of (A = 7,T=1) E. Hiyamaet al. PRC80,054321(2009) -3.79 (EXP) -4.42 Possible Charge Sym. Breaking? -5.40 (EXP) -4.42 -5.40 -6.39 -6.70.20.2(E01-011 Preliminary) 7Li(e,e’K+) (T=1)

8. 7LHe HKS-HES (E05-115) Another Physics of n Unbound neutron halo α Λ n NO DATA Bound states n α S n Direct Observation of L’s glue-like role

9. KEK E140a (1995) 28Si 28Si(e,e’K+)28Al – First Spectroscopy of 28Al Gatewayto hypernuclear spectroscopy in the medium-heavy mass region Preliminary JLAB – HKS g.s. resolution ~420 keV p d S Enriched28Si target 100 mg/cm2 30mA electron beam Counts / 0.15 MeV 28Al Accidentals Natural Si target 2000 mg/cm2 106/sec p+ beam B- Binding Energy (MeV)

10. 28Si(e,e’K+)28Al – First Spectroscopy of 28Al Gatewayto hypernuclear spectroscopy in the medium-heavy mass region Preliminary JLAB – HKS g.s. resolution ~420 keV p d S Enriched28Si target 0.1 g/cm2 30mA electron beam Counts / 0.15 MeV 28Al Motoba et al. Full shell model calc. [s4p12(sd)12] space Accidentals B- Binding Energy (MeV)

11. E05-115 HKS-HESthe 3rd generation (e,e’K+) hypernuclearspectroscopyAug. ~ Oct. 2009 • Medium - heavy hypernuclearspectroscopy 52Cr(e,e’K+) 52LV • L hyperon bound in the mean field • quark picture vs. conventional picture • Light Lhypernuclear spectroscopy • LN interaction, ls coupling, Charge Symmetry Breaking • p shell hypernuclei 7Li, 9Be,10B, 12C, 16O targets • Calibration and study of the elementary process • proton : H2O and CH2 Introduction of newly developed HES (High-resolution Electron Spectrometer)

12. PreChicane-SPL-(HKS+HES) Configuration

14. SPL : One entrance, Four exits!

16. Hypernuclei in wide mass range 1 20 50 200 1057 A E05-115 1H 7Li 9Be 10B12C 52Cr Elementary Process • Neutron/Hyperon star, Strangeness matter Strangeness electro-production Light Hypernuclei (s,p shell) • Hyperonization  • Softening of EOS ? • Superfluidity • Fine structure • Baryon-baryon interaction in SU(3) • LS coupling in large isospin hypernuclei • Cluster structure • Medium - Heavy hypernuclei • Single-particle potential • Distinguishability of a L hyperon • U0(r), mL*(r), VLNN, ... 3rd Gen. Exp. Shell model Few body calc. Bare LN Int. Mean Field Theory Cluster calc.

17. 10B target Millener’s parameterization(V,D,SN,SL,T) Hyperball’s g data predicts >200keV 1-2- separation 10B(e,e’K) p Λ n Λ α α α α Cluster Calc. based on the same framework 10Be 10B Imperfect treatment of Tensor force? Bad wavefunction of the core nucleus? Λ Λ

18. Calibration Run Missing Mass spectrum Count [/MeV] L Width of L ~4MeV (FWHM) S0 Good Coincidence! Mx-ML [MeV] count HKS-HES coin time spectrum HES mom [GeV/c] L True+Acc. Acc S0 ns HKS mom [GeV/c]

19. 12C Target Data (w/ untuned matrices) P-shell? g.s? Count [/MeV] -BL [MeV]

20. Quesi-free L & expected gs. yields • Cross section of QF L is assumed as 0.2*A0.8 [mb/sr] • # of g.s is calculated as (# of L)*(g.s cross section)/(QF L cross section) • Cross Section of 9Be is derived by Progress of Theoretical Physics Supplement No.117 (1994) pp. 151-175 (M. Sotona and S. Frullani) and other cross sections are summarized in E05-115 experiment proposal (JLab PAC 28 and 33).

21. Summary • With a high quality electron beam from CEBAF, (e,e’K) hypernuclear spectroscopy was established • The second gen. exp. E01-011 (HKS) achieved <500keV (FWHM) resolution 12B : sL width problem solved 7He : first reliable observation of g.s., CSB 28Al : first observation, doorway to mid-heavy HY • The third gen. exp. E05-115 (HKS-HES) successfully finished L : Calibration, Elementary Process 7He : CSB, L glue-like role 9Li : p-shell Hy 10Be : CSB, Tensor force, Sheds light on 10B problem 12B : Reference data & core excited states 52V : First mid-heavy HY data, core-config. mixing, ls-force Final Check of Analysis Preparing for publication Preparing mass production of 1st condensed data set