Brad Sawatzky / JLAB Acknowledgements to Liguang Tang Hampton University/JLAB MESON 2012 Krakow, Poland

INTRODUCTION  Goals:  To understand YN and YY interactions  To study short range interactions in baryonic media (OPE is absent in  N interaction)  To better explore nuclear structure using  as a probe (not Pauli blocked by nucleons)  Model the baryonic many body system  Study the role and the single particle nature of  in various nuclear medium and density  Shell Model with  -N Effective Potential (p N s  ) ssss V  N = V 0 (r)+V  (r)s N  s  +V  (r)L N   s  +V N (r)L N   s N +V T (r)S 12 Additional Contribution:  -  coupling V —  SS SNSN T Radial Integrals Coefficients of operators 

4  He 4H4H 3H3H 7  He 7  Li 6  He B  (MeV) 5  He 9  Be 9  Li 8  Be 8  Li 8  He 7  Be 13  N 13  C 10  B 12  B 11  B 9B9B Important source of data but lack statistics and resolution Reliability: Questionable

Missing predicted gamma ray

THEORY: DOUBLETS OF P-SHELL HYPERNUCLEI J p u J p l  E exp 7  Li 3/2 + 1/  Li 5/2 + 3/  Be 3/2 + 5/  = 0.430MeV S  = MeV S N = MeV T = 0.030MeV (  strength is solved and calculated by other means) Contributions in keV   S  S N T  E th However, they need to be modified for heavier hypernuclei  = 0.330MeV S  = MeV S N = MeV T = MeV J p u J p l  E exp 11  B 7/2 + 5/  B 3/2 + 1/  C  N 3/ /  O  O Contributions in keV   S  S N T  E th

CALCULATED CONTRIBUTIONS TO GROUND STATE B  (EXAMPLES)  Mass spectroscopy and level structures with precise binding energy measurement is very important  Agreement between theory and limited experimental results is not consistently good (~15-20%) Contributions in keV J p (g.s.)   S  S N T Sum 7  He 1/  Li 1/  Li 3/  Be 1/  Be 1/  B  B 5/  B  B 1/  C 1/  N 3/  N JLAB

KEK336 2 MeV(FWHM) KEK E MeV(FWHM) High resolution, high yields, and systematic study is essential. These are the “keys” to unlock the “gate”. Meson beam lacks absolute mass calibration (no solid neutron target) BNL 3 MeV(FWHM)

ELECTRO-PRODUCTION USING CEBAF BEAM  High quality primary beam allows high precision mass spectroscopy on  -hypernuclei  Producing  and  0 from proton simultaneously allows absolute mass calibration – precise binding energy  Mirror and neutron rich hypernuclei comparing those from (  +,K + ) reaction  Spectroscopy dominated by high spin-stretched spin-flip states  Results are important in determining , S N and V 0 terms from  s states and S  term from states with  at higher orbits

 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 Beam Dump Target Electron Beam Focal Plane ( SSD + Hodoscope ) K + K + Q D _ D 0 1m Q D _ D Side View Top View Target (1.645 GeV) Phase I E K+K+ e’ Phase II E Common Splitter Magnet  New HKS spectrometer  large   Tilted Enge spectrometer  Reduce e’ single rate by a factor of  High beam luminosity  Accidental rate reduced by factor of 4  High yield rate  First possible study beyond p shell

 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 Beam 2.34 GeV e’ K+K+  e Phase III E Common Splitter Magnet

6GEV PROGRAM HIGHLIGHTS 6GEV PROGRAM HIGHLIGHTS  00 Allowing precise calibration of mass scale p(e, e’K+)  and  0 (CH2 target)

B  (MeV) 28 Si(e, e’K + ) 28  Al (Hall C E01-011) HKS JLAB Counts (150 keV/bin) 28  Al ss pp dd Accidentals -B  (MeV)  0.02  0.2 MeV from  nn 7  He E in Hall A (2003 & 04)  s (2 - /1 - )  p (3 + /2 + ’s) Core Ex. States ~635 keV FWHM 12  B 6GEV PROGRAM HIGHLIGHTS– CONT. K+K+ _ D K+K+ 1.2GeV/c Local Beam Dump E Λ B spectrum ~800 keV FWHM HNSS in 2000 ss pp Phase I in Hall C (E89-009) Phase II in Hall C (E01-011) ~500 keV FWHM HKS in  B ss pp Phase III in Hall C (E05-115) ss pp

6GEV PROGRAM HIGHLIGHTS – CONT. ( 6GEV PROGRAM HIGHLIGHTS – CONT. ( PHASE III EXPERIMENT E05-115) 9  Li spectrum, Hall C HKS E (2009) B  =  0.18 (emulsion, average over only 8 events) ss ss ss Sotona and Millener Saclay-Lyon model for elementary process ss Ex: 0.0 ~0.8 ~1.6 ~ 2.6 ~3.6 ~4.0 Hall C HKS E B  = -9.8  0.3 ~4.6

6GEV PROGRAM HIGHLIGHTS – CONT. ( 6GEV PROGRAM HIGHLIGHTS – CONT. (PHASE III EXP. E IN WHICH 52  V HAS NOT YET ANALYZED ) ΛsΛs ΛsΛs ΛsΛs E ΛsΛs 3/ /2 - 7/ / /2 - 1/ / / / / Low Lying 9 Be Level Structure (< 0.1) 10  Be Theory 7/

6GEV PROGRAM TECHNIQUE SUMMARY  Hall A experiment (Pair of Septums + two HRS)  Advantage: Almost no accidental background and be able to study elementary process at low Q 2 at forward angle  Disadvantage: Low yield rate and cannot study heavier hypernuclei  Hall C experiment (Common Splitter + HKS + HES/Enge)  Advantage: High yield rate and high precision in binding energy measurement  Disadvantage: High accidental background and solid targets only Future program: Combination

EXPERIMENTAL LAYOUT IF IN HALL C HKS - Kaons Enge - Pions HES - Electrons Hodoscope Lucite Č Drift Chamber 64mg/cm 2 22mg/cm 2 K+K+ -- Trigger I: HKS(K) & Enge(  ) for Decay Pion Spectroscopy Experiment Trigger II: HKS(K) & HES(e’) for Mass Spectroscopy Experiment Is there enough space between SHMS and HMS?

Experimental Layout If in Hall A HRS - Electron HKS - Kaons HES - Pions 64mg/cm 2 22mg/cm 2 K+K+ -- Trigger I: HRS(K) & Enge(  ) for Decay Pion Spectroscopy Experiment Trigger II: HRS(K) & HRS(e’) for Mass Spectroscopy Experiment Is there scheduling problem? Are there sufficient utilities?

 High quality with low background  High precision on binding energy and high resolution  High yield rate which leads to wide range of physics:  Elementary production at forward angle  Detailed and precise level structure of light and medium heavy hypernuclei (shell models)  Precise shell structure of heavy hypernuclei (single particle nature and field theory)  High efficiency and productivity: one exp.  4—5 6GeV experiments  New physics: Decay pion spectroscopy (Light Hypernuclei)  Precise ground state B   Determination of ground state J p  Search for neutron rich limit (high Isospin states   ) Technical Features of Future Program

110 ~ 160 MeV/c ~ MeV/c110.1 ~ MeV/c ~ MeV/c ~ MeV/c Possible observation 4  H ground state Different histograms have different binning; central peak remains Central Mom. : MeV/c → B Λ ( 4 Λ H) : ~ － 1.60 MeV Width : 97 keV/c FWHM Target straggling loss was not corrected Spec-C momentum calibration was not yet done MAMI-C Short Test Run on Decay Pion Spectroscopy

SUMMARY  Hypernuclear Physics is an important part of nuclear physics  Program with CEBAF beam is the only one that provides precise B  and features Precision mass spectroscopy  Future program will be highly productive High yields, low backgrounds Simultaneous pion decay measurement