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

Hypernuclear Spectroscopy L N interaction (r) ✔ most of information is carried by the spin dependent part ✔ doublet splitting is determined by D, sL, T

new aspects of hyernuclear structure production of mirror hypernuclei  Charge Symmetry Breaking ?

Hall A Kaon collaboration 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,

Hall C hardware contribution

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

✓ p(e,e′K+)L/S The 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 failure of existing models to describe the data suggests the reaction mechanisms may be incomplete. ✓ 7Li(e,e’k) 7LHe A clear peak of the 7He ground state for the first time. CSB term puzzle, (CSB term is essential for A=4 hypernuclei).  our understanding of the CSB effect in the N L interaction potential is still imperfect. ✓ 9Be(e,e’K+)9LLi: Disagreement between the standard model of p-shell hypernculei and the measurements, both for the position of the peaks and for the cross section. ✓ 12C(e,e’K+) 12LB: for the first time a measurable strength with sub-MeV energy resolution has been observed in the core-excited part of the spectrum. The s part of the spectrum is well reproduced by the theory, the p shell part isn’t. ✓.16O(e,e’K+)16LN: The fourth peak ( in p state) position disagrees with theory. This might be an indication of a large spin-orbit term SL. Binding Energy BL=13.76±0.16 MeV measured for the first time with this level of accuracy

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

Decay Pion Spectroscopy to Study -Hypernuclei Direct Production p e’ e 12C K + Example:  Hypernuclear States: Λs (or Λp) coupled to low lying core nucleus 1- 0.0 2- ~150 keV Ground state doublet of 12ΛB Precise BΛ Jp and  γ*  12ΛBg.s. E.M.  12ΛB 12C  - Weak mesonic two body decay ( -  0.1) 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

Summary and outlook Hypernuclear Spectroscopy by e.m. probe successfully established at Jlab confirming its excellence for studying hypernuclei The experiments required important, challenging modifications to the Hall A and Hall C detector setup Crucial contributions from Italian and Japanese collaborations The new equipment performed excellently. Best characteristics of Hall A and Hall C detectors setup understood Merging collaborations and getting the best out of the two detectors in order to best continue into the 12 GeV era Jlab beam and detectors make it unique in the international panorama for this physics

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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

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

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

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

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

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

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

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.

An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) The First reliable observation of 7LHe Old result on 7LHe (M.Juric et al. NP B52 (1973) 1) Inadequate for a serious comparison 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.

An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) -BL (MeV) -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! 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.

An example of what we learn from Hypernuclei A Highlight of JLab E01-011 (HKS) -BL (MeV) -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. 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.

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

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

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

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 hypernuclei which 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 connected to the well known structure of the decay nucleus, allow determination of B and spin-parity of the ground state of hyperfragments, study CSB