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Decade of Hypernuclear Physics at JLAB and Future Prospective in 12 GeV Era

Decade of Hypernuclear Physics at JLAB and Future Prospective in 12 GeV Era. Liguang Tang Department of Physics, Hampton University & Jefferson National Laboratory (JLAB). August 8 - 11, 2011, Hadron Physics 2011, Shandong University. Introduction – Hypernuclei.

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Decade of Hypernuclear Physics at JLAB and Future Prospective in 12 GeV Era

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  1. Decade of Hypernuclear Physics at JLAB and Future Prospective in 12 GeV Era Liguang Tang Department of Physics, Hampton University & Jefferson National Laboratory (JLAB) August 8 - 11, 2011, Hadron Physics 2011, Shandong University

  2. Introduction – Hypernuclei • Baryonic interactions are important nuclear physics issues to extend the QCD descriptions of single nucleon (its form factors, etc…) to strongly interactive nuclear many body system • A nucleus with one or more nucleons replaced by hyperon, such as , , …  a Hypernucleus • Hypernucleus is a unique tool and a rich laboratory to study YN and YY interactions  baryonic interactions beyond NN • Study  hypernuclei is an important gate way to the   interaction

  3. Unique Features of -Hypernuclei • Long lifetime: -hypernucleus in ground state decays only weakly via    N or N NN, thus mass spectroscopy features with narrow states (< few to 100 keV) • Description of a -hypernucleus within two-body frame work – Nuclear Core (Particle hole)   (particle): VΛN(r) = Vc(r) + Vs(r)(SΛ*SN) + VΛ(r)(LΛN*SΛ) + VN(r)(LΛ*SN) + VT(r)S12 • Absence of OPE force in N: Study short range interactions •  is a“distinguish particle” to N (i.e. no Bauli Blocking): a unique probe to study nuclear structure • Trace the single  particle nature in heavy hypernuclei allows to study the nuclear mean field Hypernuclear physics is an important component in nuclear physics

  4. Advantage of Electro-production Hypernuclei (e, e’K) Reaction • New spin structure due to photon absorption and large momentum transfer -Strong spin flip amplitudes • Highest possible spin • Neutron rich hypernuclei (N-N coupling) • High resolution 1.5 MeV (hadronic production)  <500keV • High accuracy B  50keV is possible • Technical challenges • Require small forward angles • High particle singles rates • Accidental coincidence rate • Challenging optics and kinematics calibration e e’  K+ p  • Low-lying states • Lowest few and most stable core • states (particle hole states) • Narrow hypernuclear states with •  coupled at different shell levels • Non-spin flip (natural parity) states • or spin flip (unnatural parity) states • These states are most studied A A

  5. Hall A Technique • Two Septum magnets -Independent two arms • No problem for post beam • Low e’ singles rate • Low accidental background • Difficulties • High hadron momentum which which is resolved by RICH detector • High luminosity but low yield rate (long spectrometers and small acceptances) HRS - Hadron K+ Septum e e’ HRS - Electron

  6. K+ e’ Hall C Technique Common Splitter Magnet Phase I Side View Phase II + K Target _ D D Q • Zero degree e’ tagging • High e’ single rate • Low beam luminosity • High accidental rate • Low yield rate • A first important milestone for • hypernuclear physics with electro- • production • New HKS spectrometer  large  • Tilted Enge spectrometer  Reduce e’ • single rate by a factor of 10-5 • High beam luminosity • Accidental rate improves 4 times • High yield rate • First possible study beyond p shell Top View _ Q Electron + K Beam D D (1.645 GeV) Target Focal Plane ( SSD + Hodoscope ) Beam Dump 0 1m

  7. Hall C Technique – Cont. Common Splitter Magnet Phase III • New HES spectrometer  larger  • Same Tilt Method • High beam luminosity • Further improves accidental rate • Further improves resolution and • accuracy • High yield rate • First possible study for A > 50 e  e’ K+ Beam 2.34 GeV

  8. Results on H target – The p(e,e’K+)Cross Section (Hall A) p(e,e'K+)Production run (Waterfall target)  p(e,e'K+) Calibration run (LH2 Cryo Target) Expected data from E07-012, study the angular dependence of p(e,e’K+)and 16O(e,e’K+)16Nat low Q2  • None of the models is able to describe the data • over the entire range • New data is electro-production – could longitudinal • amplitudes dominate? o 10/13/09

  9. JLab E01-011 (HKS, Hall C) -6.730.020.2 MeV from a L n n First reliable observation of 7He Test of Charge Symmetry Breaking Effect. A Naïve theory does not explain the experimental result. Jlab E05-115 -BL (MeV) A Naïve calculation on CSB effect, which explains 4LH – 4LHe and available s, p-shell hypernuclear data , gives opposite shifts to A=7 ,T=1 iso-triplet L Hypernuclei.

  10. Hall A Result on 9Li Spectroscopy Spectroscopy is still under study and not yet published.

  11. The 12B Spectroscopy (Hall A & C) E94-107 in Hall A (2003 & 04) Phase I in Hall C (E89-009) ~635 keV FWHM s (2-/1-) p (3+/2+’s) s p ~800 keV FWHM E89-009 12ΛB spectrum HNSS in 2000 Core Ex. States K+ Phase II in Hall C (E01-011) • HKS 2005 has incorrect optics optics • tune – affecting the line shape • The source is found from Phase III • 2009 HKS-HES experiment and the • correct method is developed • 2005 optics tune and kinematics • calibration is under redoing together • with the 2009 data • The goals are • Precise binding energy • High resolution • Resolve doublet separations HKS in 2005 ~500 keV FWHM Red line: Fit to the data Blue line: Theoretical curve: Sagay Saclay-Lyon (SLA) used for the elementary K-Λ electroproduction on proton. (Hypernuclear wave function obtained by M.Sotona and J.Millener) M.Iodice et al., Phys. Rev. Lett. E052501, 99 (2007) _ K+ 1.2GeV/c D Local Beam Dump

  12. The Expected 12B Spectroscopy 13.05 12.95  Threshold 11.05 10.98 10.52 10.48 1+ 2+ P 5.85 P3/2 5.74 3+ 2+ 1+ 2+ 7Li +  (8.665) 5/2- 8.559 2.67 3/2+ 7.978 P3/2 (3/2, 5/2)+ 7.286 P1/2 6.793 1/2+ P 0.14 0.0 P3/2 Theoryg S1/2 1- 2- S1/2  F. AJZENBERG-SELOVE and C. L. BUSCH, Nuclear Phystcs A336 (1980) 1-154. g D.J. Millener, Nuclear Phystcs A691 (2001) 93c. Pmeans a mixing of 1/2 and 3/2 states. 2- S1/2 S1/2 0- 7/2- 3/2- 1/2- 5/2- 4.445 5.021 6.743 2.1248 1- S1/2 3/2- 0.0 S1/2 2- 1- S1/2 11B 12B

  13. Results on 16Otarget – Spectroscopy of 16 N (Hall A) F. Cusanno et al, PRL 103 (2009) Fit 4 regions with 4 Voigt functions c2/ndf = 1.19 Binding Energy BL=13.76±0.16 MeV Measured for the first time with this level of accuracy (ambiguous interpretation from emulsion data; interaction involving L production on n more difficult to normalize) Within errors, the binding energy and the excited levels of the mirror hypernuclei 16O and 16N (this experiment) are in agreement, giving no strong evidence of charge-dependent effects 0.0/13.760.16

  14. KEK E140a SKS Spectroscopy of 28Al (Hall C) 28Al 28Si(e, e’K+)28Al HKS JLAB d HKS (Hall C) 2005 p • 1st observation of 28Al • ~400 keV FWHM resol. • Clean observation of the shell structures s Wider Narrower Peak B(MeV)Ex(MeV)Errors (St. Sys.) #1 -17.820 0.0 ± 0.027± 0.135 #2 -6.912 10.910 ± 0.033± 0.113 #3 1.360 19.180 ± 0.042± 0.105 Counts (150 keV/bin) 28Si(p+,K+)28Si Accidentals B (MeV)

  15. Additional Data By HKS-HES (Hall C, 2009) • 2009 data analysis is ongoing • Current analysis: kinematics calibration and spectrometer optics optimization • Additional data for existing spectroscopy 7He, 9Li, and 12B (more statistics and better precision) • New data: • 10Be (puzzle of gamma spectroscopy) • 52V(further extend beyond p shell)

  16. New Concept in 12 GeV Era: Study of Light -Hypernuclei by Spectroscopy of Two Body Weak Decay Pions Fragmentation of Hypernuclei and Mesonic Decay inside Nucleus Free:  p + - 2-B: AZ  A(Z + 1) + -

  17. Decay Pion Spectroscopy to Study -Hypernuclei Direct Production e’ Example: K+ 12C e * Ground state doublet of 12B Precise B Jp and  p  12B  E.M. Hypernuclear States: s (or p) coupled to low lying core nucleus 2- ~150 keV - 1- 0.0 12C Weak mesonic two body decay 12Bg.s. 

  18. Decay Pion Spectroscopy for Light and Exotic -Hypernuclei Fragmentation Process Example: e’ K+ Access to variety of light and exotic hypernuclei, some of which cannot be produced or measured precisely by other means 12C e * Fragmentation (<10-16s) p s 12B* 4H  4Hg.s. Highly Excited Hypernuclear States: s coupled to High-Lying core nucleus, i.e. particle hole at s orbit  -   Weak mesonic two body decay (~10-10s) 4He  

  19. Study of Light Hypernuclei by Pionic Decay at JlabTechnique and Precision • High yield of hypernuclei (bound or unbound in continuum) makes high yield of hyper-fragments, i.e. light hypernuclei which stop primarily in thin target foil • High momentum transfer in the primary production sends most of the background particles forward • Precision does not depend on the precisions of beam energy and tagged kaons • The momentum resolution can be at level of ~170keV/c FWHM, powerful in resolving close-by states and different hypernuclei • Bcan be determined with precision at a level of 20keV • The experiment can be carried out in parasitic mode with high precision hypernuclear mass spectroscopy experiment which measures the level structures of hypernuclei • Physics analysis is more complicated while achieving high resolution is rather simple

  20. Study of Light Hypernuclei by Pionic Decay at JlabMajor Physics Objectives • Precisely determine the single  binding energy B for the ground state of variety of light hypernuclei: 3H,4H, ..., 11Be, 11B and12B , i.e. A = 3 – 12 (few body to p shell) • Determine the spin-parity Jpof the ground state of light hypernuclei • Measure CSB’s from multiple pairs of mirror hypernuclei such as: • 6He and6Li, 8Li and8Be, 10Be and10B. • CSB can also be determined by combining with the existing emulsion result for hypernuclei not measured in this experiment • Search for the neutron drip line limit hypernuclei such as: 6H, 7H and 8H which have high Isospin and significant - coupling • May also extract B(E2) and B(M1) electromagnetic branching ratios through observation of the isomeric low lying states and their lifetimes. • The high precision makes these above into a set of crucial and extremely valuable physics variables which are longed for determination of the correct models needed in description of the Y-N and Y-Nucleus interactions.

  21. Study of Light Hypernuclei by Pionic Decay at JlabIllustration on the Main Features Comparison of Spectroscopic and Background - Production SPECTROSCOPY Light Hypernuclei to Be Investigated e e p * - K+ p  A1Z1 stop (b) Additions from 9Li and its continuum (Phase II: 9Be target) 6 3/2+ AZ 1/2+ Jp=? VS 1- A2Z2 7Li A(Z-1) A1(Z1+1) 8He 9Li 8Li 5 (Z-1) = Z1+Z2; A=A1+A2 6Li 1/2+ 7H 3B background 1-? 5/2+ 3/2+ 2- 4 BACKGROUND e Previously measured e Ex Ex Ex 0 0 0 1 1 1 * 3 Mirror pairs K+ Ex 0 2 - p(n) ,(-) N 2 AZ (A-1)Z’ 8Be 8B 9Li 8H 7He 6He 9B 8He 3H 6Li 10Be 10Li 10B 12B 9He 7Li 9Be 5H 4H 6H 8Li 7H 11Be 11B 1 A 2 6 7 11 12 8 1 5 3 4 9 10

  22. Illustration of Decay Pion Spectroscopy Additions from 12B and its continuum (Phase III: 12C target) (c) 1- 12B 9Be 10Be 8Be 9B 11B 10Li 9He 11Be 8H Jp=? 10B 5/2+ 3B background 8B (b) Additions from 9Li and its continuum (Phase II: 9Be target) 3/2+ 1/2+ 1- 7Li 8He 9Li 8Li 6Li 1/2+ 7H 3B background 1-? 5/2+ 3/2+ 2- Ex Ex Ex (a) 0 0 0 1 1 1 2-B decay from 7He and its continuum (Phase I: 7Li target) Ex 0 2 1-? 0+ 1/2+ 3H 6He 1/2+ 6H 4H 7He 3B background 3/2+ 5H 5/2+ Ex PMax PMin Ex 2 0 0 2 90.0 100.0 110.0 120.0 130.0 140.0 - Momentum (MeV/c)

  23. Experimental Layout (Hall A) in 12GeV Era HRS - Electron 64mg/cm2 22mg/cm2 K+ HES - Pions HKS - Kaons - Trigger I: HRS(K) & Enge() for Decay Pion Spectroscopy Experiment Trigger II: HRS(K) & HRS(e’) for Mass Spectroscopy Experiment

  24. Hypernuclei in wide mass range E89-009, E01-011, E05-115(Hall C) E94-107(Hall A) 1 20 50 200 1057 A Future mass spectroscopy H, 7Li, 9Be, 10B, 12C, 16O, 28Si, 52Cr Elementary Process Strangeness electro-production • Neutron/Hyperon star, • Strangeness matter • Hyperonization  • Softening of EOS ? • Light Hypernuclei (s,p shell) • Fine structure • Baryon-baryon interaction in SU(3) • LS coupling in large isospin hypernuclei • Cluster structure • Medium/heavy Hypernuclei • Single particle potential • Distinguish ability of a  hyperon • Uo(r), m*(r), VNN, … • Decay Pion Spectroscopy • (Light Hypernuclei) • Precise B of ground state • CSB • Spin-parity Jp of ground state • Extreme isospin • N system • …

  25. Summary • High quality and high intensity CW CEBAF beam at JLAB made high precision hypernuclear programs possible. Programs in 6GeV era were successful. • Together with J-PARC’s new programs, as well as those at other facilities around world, the hypernuclear physics will have great achievement in the next couple of decades. • The mass spectroscopy program will continue in 12 GeV era with further optimized design • The new decay pion spectroscopy program will start a new frontier

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