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HYPERNUCLEAR PHYSICS

HYPERNUCLEAR PHYSICS. Perspectives of Hypernuclear Physics at Jlab in the 12 GeV era F. Garibaldi on behalf of Jlab hypernuclear collaboration. Hypernuclei are bound states of nucleons with a strange baryon ( L hyperon ). Extension of physics on N-N interaction to system with S#0

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HYPERNUCLEAR PHYSICS

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  1. HYPERNUCLEAR PHYSICS PerspectivesofHypernuclearPhysics at Jlab in the 12 GeV era F. Garibaldi on behalfofJlabhypernuclearcollaboration • Hypernuclei are bound states of nucleons with a strange baryon (Lhyperon). • Extension of physics on N-N interaction to system with S#0 • Internal nuclear shell • are not Pauli-blocked • for hyperons • Spectroscopy Few-body aspects and YN, YY interaction Mean field aspects of nuclear matter Astrophysical aspect - N interaction • L-N force vs N-N force will provide clues to the QCD description of the N-N Force (one-p and one-r exchange suppressed) many body problems

  2. HypernuclearSpectroscopy L Ninteraction (r) V ✔ most ofinformationis carried out by thespin dependent part ✔ doublet splittingdetermined byD, sL, T

  3. newaspectsofhyernuclearstructure production of mirror hypernuclei Charge Symmetry Breaking ?

  4. Hall A Kaoncollaboration F.Garibaldi (INFN), S. Frullani (INFN). M.Iodice (INFN), J.LeRose (Jlab), P. Markowitz (FIU),G. Chang (Maryland) E94-107- E-98-108 - E 07-012 96 collaborators - 30 Institutions,

  5. Hall C hardware contribution

  6. Hall A deector setup RICH Detector hadron arm septum magnets electron arm aerogel first generation aerogel second generation To be added to do the experiment

  7. ✓p(e,e′K+)L/SThe data suggest that not only do the present models fail to describe the data over the full angular range, but that the cross section rises at the forward angles. The failureofexistingmodelstodescribe the data suggests the reactionmechanismsmaybe incomplete. ✓7Li(e,e’k) 7LHe A clearpeakof the 7Heground state for the first time. CSB termpuzzle, (CSB termisessentialfor A=4 hypernuclei).  understanding of the CSB effect in the N L interaction potential is still imperfect. ✓9Be(e,e’K+)9LLi: Disagreementbetween the standard modelofp-shellhypernculei and the measurements, bothfor the positionof the peaksandfor the cross section. ✓12C(e,e’K+) 12LB: for the first timea measurablestrengthwithsub-MeVenergyresolutionhasbeenobserved in the core-excited part of the spectrum. The s part of the spectrumiswellreproducedby the theory, the pshell part isn’t. ✓.16O(e,e’K+)16LN: The fourthpeak( in p state) position disagreeswiththeory. Thismightbeanindicationof a largespin-orbitterm SL. Binding Energy BL=13.76±0.16 MeVmeasured for the first time with this level of accuracy

  8. Hypernuclei in a wide mass range E05-115 6,7Li 10,11B 12C 51V 52Cr 89Y E-94-107 1 20 50 200 1057 A 208Pb 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, ... Shell model Few body calc. Mean Field Theory Bare LN Int. Cluster calc.

  9. 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 ( - 0.1) 12Bg.s.  - Weak 2 body mesonic decay at rest uniquely connects the decay pion momentum to the well known structure of the decay nucleus, B and spin-parity of the ground state of hyperfragment

  10. Summary and outlook • HypernuclearSpectroscopybye.m. probe successfullyestablished at Jlabconfirmingtobeexcellenttooltostudyhypernuclei • The experimentsrequiredimportant, challengingmodifications on the Hall A and Hall C detector setup • CrucialcontributionsfromItalian and Japanesecollaborations • The newequipmentsshowed excellent performance. • Best characteristicsof Hall A and Hall C detectors setup understood • Merging collaborations and getting the best out of the two detectors • to be able to do next step in 12 GeV era • Jlab beam and detectors make it unique in the international panorama for this physics

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  12. YN, YY Interactions and Hypernuclear Structure Free YN, YY interaction Constructed from limited hyperon scattering data (Meson exchange model: Nijmegen, Julich) G-matrix calculation YN, YY effective interaction in finite nuclei (YN G potential) Hypernuclear properties, spectroscopic information from structure calculation (shell model, cluster model…) Energy levels, Energy splitting, cross sections Polarizations, weak decay widths high quality (high resolution & high statistics) spectroscopy plays a significant role

  13. H.-J. Schulze, T. Rijken PHYSICAL REVIEW C 84, 035801 (2011)

  14. Hypernuclei in the wide mass range -- toward strange matter -- • Short range nature of the LN interaction : no pion exchange • meson picture or quark picture ? • Light hypernuclei (A<~20) • Fine structure • Baryon-baryon interaction in SU(3) • LS coupling in large isospin hypernuclei • Cluster structure • Heavy hypernuclei (A>~50) • Single-particle potential • Distinguishability of a L hyperon • U0(r), mL*(r), VLNN, ... • Neutron star (A ~ 1057 ) • Hyperonization  Softening of EOS ? • Superfluidity

  15. Understanding the N-N Force In terms of mesons and nucleons: Or in terms of quarks and gluons: V =

  16. Hypernuclei Provide Essential Clues For the N-N System: For the L-N System:

  17. Hypernuclei Provide Essential Clues For the N-N System: For the L-N System: Long Range Terms Suppressed (by Isospin)

  18. L single particle energies E05-115(HKS-HES) E01-011(HKS) E94-107 (Hall A HY) Calculation by John Millener, using a Woods-Saxon potential with a depth of 28 MeV and a radius parameter of 1.128 + 0.439A-2/3

  19. JLab’s Hypernuclear Program To Date

  20. An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) The First reliable observation of 7LHe A Test of Charge Symmetry Breaking • Begin with a theoretical description of these nuclei without CSB

  21. An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) The First reliable observation of 7LHe A Test of Charge Symmetry Breaking • Begin with a theoretical description of these nuclei without CSB • A Naïve calculation of the CSB effect, which explains 4LH –4LHe and available s, p-shell hypernuclear data, predicts opposite shifts for A=7 ,T=1 iso-triplet L Hypernuclei.

  22. An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) Old result on 7LHe (M.Juric et al. NP B52 (1973) 1) Inadequate for a serious comparison The First reliable observation of 7LHe A Test of Charge Symmetry Breaking • Begin with a theoretical description of these nuclei without CSB • A Naïve calculation of the CSB effect, which explains 4LH –4LHe and available s, p-shell hypernuclear data, predicts opposite shifts for A=7 ,T=1 iso-triplet L Hypernuclei.

  23. An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) -6.730.020.2 MeV from a L n n The First reliable observation of 7LHe A Test of Charge Symmetry Breaking Compare with new measurements of 7LHe Measured shift has the opposite sign to the predicted shift! -BL (MeV) • Begin with a theoretical description of these nuclei without CSB • A Naïve calculation of the CSB effect, which explains 4LH –4LHe and available s, p-shell hypernuclear data, predicts opposite shifts for A=7 ,T=1 iso-triplet L Hypernuclei.

  24. An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) -6.730.020.2 MeV from a L n n The First reliable observation of 7LHe A Test of Charge Symmetry Breaking Naïve theory does not explain the experimental result. -BL (MeV) • Begin with a theoretical description of these nuclei without CSB • A Naïve calculation of the CSB effect, which explains 4LH –4LHe and available s, p-shell hypernuclear data, predicts opposite shifts for A=7 ,T=1 iso-triplet L Hypernuclei.

  25. Present Status of L Hypernuclear Spectroscopy (2011) Tremendous Progress, but More Nuclei and Higher Precision are Needed To Fully Understand the L-N/N-N Force Differences  JLab and JPARC Programs 52LV Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564.

  26. Complementary Additional Measurements Proposed for the 12 GeV Upgrade The addition of measurements of p decay of hypernuclei will permit • Precise (~±20 keV) determination of  binding energies of a variety of ground state light hypernuclei • Determination and confirmation of ground state spin/parity • Direct measurement of  binding energy differences from multiple mirror pairs of light hypernuclei at ground state to investigate CSB and Coulomb effect • Searching for the neutron drip line limit of light hypernuclei – heavy hyper-hydrogen • Searching for evidence of the existence of isomeric hypernuclear states • Studying impurity nuclear physics – B(E2) measurement and medium effect of baryons – B(M1) measurement through lifetime

  27. ✓Few-body aspects and YN, YY interaction ✓Mean field aspects of nuclear matter ✓Many body andastrophysical aspect

  28. PR12-10-001 - 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) + - High yield and unique decay feature allow high precision measurement of 2 body decay pion spectroscopy from which variety of physics may be extracted Decayat rest the pion momentum is uniquely connected to the well known structure of the decay nucleus, allow determination of B (~20keV) and spin-parity of the g.s. of hyperfragments, study Charge Symmetry Breaking (CSB)

  29. PR12-10-001 - 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) + - High momentum transfer in the primary production sends most of the background particles forward, thus pion momentum spectrum is expected to be clean with minor 3-boby decay pions: • High yield of hypernuclei (bound or unbound in continuum) makes high yield of hyper fragments, i.e. light hypernucleiwhich • stop primarily in thin target foil High yield and unique decay feature allow high precision measurement of 2 body decay pion spectroscopy from which variety of physics may be extracted - Decay at rest the pion momentum is uniquely connectedto the well known structure of the decay nucleus, allow determination of Band spin-parity of the ground state of hyperfragments, study CSB

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