Spectroscopic study of  hypernuclei in the medium-heavy mass region and p-shell region using the (e,e’K + ) reaction (PR08-002) JLab PAC33 16, Jan, 2008 (Wed) Satoshi N. Nakamura Tohoku Univ.

New proposal to PAC33 Based on the analysis experiences of E (HKS), we need more calibrations Medium-heavy region, high quality data for 40 Ca target is longed. Recent progresses on p-shell hypernuclear theories, more data on 7 Li, 10 B. Additional beam time request to the partially approved E (HES)

Hypernuclear Programs at JLab 2000 E (Hall C) First (e,e’K) hypernuclear spectroscopy E Λ B spectrum Beam: 0.66 μ A, 1.8 GeV SOS: Δ p/p=5 x [FWHM] Solid angle 4 msr(w/ splitter) Enge: Δ p/p=5 x [FWHM] ~ 2 months data Resolution < 1 MeV [FWHM] 12  B (gs) Yield < / h (165 counts / 440 h) Successfully Demonstrated : (e,e’K) spectroscopy is Possible! First Generation T.Miyoshi et al. PRL 90 (2003) L.Yuan et al. PRC 73 (2006)

Hypernuclear Programs at JLab 2004,5 E (Hall A) p-shell hypernuclear spectroscopy ( 12 C, 9 Be, 16 O) Beam: 100 μ A, 4GeV HRS: Δ p/p=2.5 x [FWHM] Solid angle 4.5 msr(w/ septum) Hall A Experiment Resolution 650 keV [FWHM] 12  B (gs) Yield ~ 2-4 / h M.Iodice et al. PRL 99 (2007) Excellent S/N Water Fall Target

Hypernuclear Programs at JLab Second Generation 2005 E (Hall C) First step to beyond p-shell hypernuclei (main target 28 Si, calib. 12 C) Introduction of Tilt ENGE e’ rate surpression Resolution <400 keV [FWHM] 12  B (gs) Yield ~ 8 / h Newly introduced HKS worked fine Counts/150keV ENGE HKS Splitter Electron beam To beam dump Target

Hypernuclear Programs at JLab Approved Experiments at Hall C&A Excellent S/N ratio Water Fall Target = H 2 O Hypernuclear yield improvement by HES Hall A = HRS + HRS + Septum E E Elementary process & Detailed study on 16  N Counts/150keV E E p(e,e’K)  Future Experiments Third Generation High e’ BG suppression by Tilt Method Mid-heavy target can be used Hall C = HKS + HES + SPL Wide mass range study with excellent resolution 12  B 2 nd Generation

Hypernuclei in wide mass range Medium - Heavy hypernuclei Neutron/Hyperon star Light Hypernuclei (s,p shell) A Elementary Process Strangeness electro-production Fine structure Baryon-baryon interaction in SU(3)  coupling in large isospin hypernuclei Cluster structure Hyperonization  Softening of EOS ? Superfluidity Single-particle potential Distinguishability of a  hyperon U 0 (r), m  *(r), V  NN,... E C E Li 12 C 28 Si Neutron/Hyperon star, Strangeness matter E Be 12 C 16 O Shell model Bare  N Int. Few body calc. Mean Field Theory Cluster calc.

Hypernuclei in wide mass range Neutron/Hyperon star, Strangeness matter Light Hypernuclei (s,p shell) A Elementary Process Strangeness electro-production Fine structure Baryon-baryon interaction in SU(3)  coupling in large isospin hypernuclei Cluster structure Hyperonization  Softening of EOS ? Superfluidity E ＆ PR ,7 Li 10 B,11 B 12 C 40 Ca 52 Cr 89 Y Single-particle potential Distinguishability of a  hyperon U 0 (r), m  *(r), V  NN,... Medium - Heavy hypernuclei 3 rd Gen. Exp. Bare  N Int. Few body calc. Mean Field Theory Cluster calc. Shell model

Various targets E First Generation E Hall A Experiment E Second Generation E Third Generation PR Third Generation Mean Field Theory Predictions

H.Hotchi et al. PRC 64 (2001)  V P.H.Pile et al. PRL 66 (1991) 2585 LS spilitting or core config. mixing Compare spectrum with Reliable Shell model Calc. A = 40A ~ Ca = (Z=20, N=20) : 40  K = one proton hole +  Response to Theory Gr. comments Approved E05-115Proposing PR Reliable E(  s ), E(  p ), E(  d ) inputs for Mean Field Theories Cross sections of various states constraint  N interaction models

The Overbinding Problem MeV MeV MeV MeV 0.0 Dalitz et al., NP B47 (1972) 109. Overbinding Problem on s-shell Hypernuclei spin-spin Overbound

The Underbinding Problem MeV MeV MeV MeV Akaishi, Harada et al., PRL 84 (2000) Underbinding Problem on s-shell Hypernuclei adjusted D2  N-  N coupling + +  NN three-body force  N-  N coupling is important Underbound

7 Li target α n n Λ α  Unbound neutron halo Bound states Direct Observation of  ’s glue-like role n n NO DATA

7 Li target (A = 7) E. Hiyama Private Comm. 7 Li(e,e’K + ) (EXP) (EXP) Possible Charge Sym. Breaking? NO DATA

Hypernuclear  -ray data since 1998 (mainly Hyperball data)

10 B target αα n Λ 10 Be Λ αα p Λ 10 B Λ Millener’s parameterization(V, ,S N,S ,T) Hyperball’s  data Imperfect treatment of Tensor force? Bad wavefunction of the core nucleus? predicts >200keV separation 10 B(e,e’K) Cluster Calc. based on the same framework

Third Generation FIRST Generation SECOND Generation SOS + ENGE + SPL HKS + ENGE + SPL HKS +HES + new SPL Tilt Method Simulation mid-heavy hypernuclei 40  K

Momentum acceptance Primary beam energy scan tune SPL+HKS/HES Pe’ and Pk scan (delta scan) tune HKS, HES (not SPL) Proposing Calibration Procedures One serious energy tune ~ 16 hours 10-20MeV may be easy with RF of fast FB Res.toTAC

p(e,e’K + )  0 CH 2 not sustain >2  A Water cell target ◦ H 2 O/D 2 O targets ◦ SS Study for  ◦ 16  N data Water Cell Target Carbon Target 12  B data Sieve Slit Raster study Counts (0.3MeV/bin) MM (MeV)   m  = MeV m  = MeV Periodic calibration with the water cell target & 12 C.

Requested beamtime in addition to E05-115

21 HKS+HES+newSPL setup CEBAF 2.5GeV Electron Beam Splitter 1.0GeV/c e ’ 1.2GeV/c K + HESHES HKSHKS HKS (incl. detectors) was commissioned in E HES detectors : EDC1 was used for ENGE EDC2 …. Spare chamber of HDC EHOD … to be beam-tested in March

HES magnets were completed and left Japan for JLab. Collaboration has been preparing for E from 2005, and will be ready for installation and beam by the end of 2008.

Summary E proved that newly introduced HKS and the tilt method worked fine. E was partially approved for wide mass range hypernuclear spectroscopy with new HES. Based on recent theoretical progresses: 7 Li(e,e’K + ) 7  He few body calc.,  N-  N couple 10 B(e,e’K + ) 10  Be 40 Ca(e,e’K + ) 40  K reliable shell model sophisticated mean field theories Calibration Beam energy scan, delta scan, Water Cell target Increase physics outputs much with the resources prepared for the approved E