LEDA / Lepton Scattering on Hadrons Hypernuclear Spectroscopy: 12 C and 16 O, 9 Be(preliminary) high quality data available. First publication soon. Extension to heavier hypernuclei under evaluation Good results on Parity (Happex) and Spin structure of neutron 3 experiments approved in January (high rate) –PREX: measurement of neutron skin in Lead –Transversity: one experiment approved on nucleon spin structure –Correlation and relativistic effects ( 208 Pb(e,e’p) 207 Tl) in the nuclear medium Member of the Hall A Collaboration at Jefferson Lab, leadership on:

E LECTROproduction of H ypernuclei at J efferson Lab H ypernuclei are bound states of nucleons with a strange baryon (Lambda hyperon). Hypernuclear physics accesses information on the nature of the force between nucleons and strange baryons. A hypernucleus is a “laboratory” to study nucleon-hyperon interaction (L-N interaction). The characteristics of the Jefferson Lab. electron beam, and those of the experimental equipments, offer a unique opportunity to study hypernuclear spectroscopy via electromagnetic induced reactions. A new experimental approach: alternative to the hadronic induced reactions studied so far. E beam ~ 4GeV K+K+ e e’ p L Hyperon formation in neutron stars is controlled by the attractive hyperon- nucleon interaction which can be extracted from hypernuclear data LEDA experiment is planning to complete a systematic study of high resolution spectroscopy on light and medium- heavy nuclei Hall A facility: Standard HRS spectrometers 2 Septum Magnets for small angle RICH detector for superior p / K /  identification

First RESULTS on 12 C and 16 O, 9 Be nuclear targets: 12 C(e,e’K) 12 B  Energy resolution ~ 700 KeV -the best achieved in hypernuclear production experiments, (improving) down to -first clear evidence of excited core states at ~2.5 and 6.5 MeV with high statistical significance - possible thanks to the RICH detector and Septum magnets (INFN contribution), important devices for other experiments (parity, GDH..) and planned(Pb Parity, Transversity..) 16 O(e,e’K) 16 N   -interaction here is in p-state, poorly known…. Data will help in improving the model parameters (Spin-Orbit term of  N interaction potential) 9 Be(e,e’p) 9 Li  Models of elementary reactions fail in reproducing the data (Red, Bennhold-Mart (K MAID)) (Blue Saclay-Lyon (SLA)) ~ 400 KeV

Q 2 ~0.1 GeV 2 Happex: “strangeness content of proton” Parity-violating electron scattering on proton and 4 He Strange form factors. anticipated precision Interference with Electromagnetic amplitude makes Neutral Current accessible Longitudinal spin asymmetry violates parity (polarized e-, unpolarized p) G E s = ± 0.29 G M s = 0.62 ± % Would imply that 7% of nucleon magnetic moment is Strange Improving precision

Pion rejection factor ~ 1000 Superconducting Septum magnets RICH detector unambiguous K identification LEDA contribution for experiments in Hall A (performed and planned) 12.5° 6 ° (>Mott cross section)

PREX: Parity Violating Electron Scattering on Pb Investigation of the nucleonic matter properties Equation of state of neutron rich matter Symmetry energy of dense matter Strong connection with neutron star properties Clean Measurement of neutron skin of lead by Left/Right Electroweak Cross Section Asymmetry: As effective probe of neutron form factor F n (Q 2 ) Accurate neutron radius determination Experimental Aspects CEBAF 80% Polarized Electron Beam Lead Foil Target Hall A Standard Spectrometers + Septum Magnets z

Single Spin Asymmetry of 3 He­(e,e’h±)X on DIS Physics Motivations: Nucleon Spin Structure: information on (poorly know) transverse quark spin and (unknown) angular momentum contribution to the nucleon spin Non-perturbative QCD: non-singlet transverse quark distribution function provides a clean Q 2 evolution Complementary to existing data (HERMES and COMPASS mainly) and unique for the coming years First Time Measurement of neutron Transverse Target Single Spin Asymmetry: Experimental Aspects CEBAF High Density Electron Beam High Density Transversely polarized 3 He target almost pure polarized neutron RICH Detector for scattered hadron (p/K) identification 26 International Institutions involved Approved experiment (Jlab) with highest rating Expected to run 2 nd semester of 2007 for 1 month

Identifying correlations and relativistic effects in the nuclear medium K. Aniol, A. Saha, J. M. Udias and G. Urciuoli Spokepersons The experiment will use 208 Pb, a doubly magic, complex nuclei, a textbook case for the shell model, measuring 208 Pb(e,e’p) 207 Tl cross sections at true quasielastic kinematics and at both sides of q. This has never been done before for A>16 nucleus (1)First measurements in quasielastic kinematics on the paradigmatic shell model nucleus, 208 Pb at high Q 2. Accurate spectroscopic factors for separated shells will be obtained at several values of Q 2. (2)Strength for p miss > 300 MeV/c will give insight into nuclear structure issues and will settle the long standing question about the amount of long range correlations. They will be seen for the first time, if they are there. (3)A new observable A TL for the five low lying states of 207 Tl will be measured. A TL helps distinguishing between relativistic and nonrelativistic structure of the wave functions. Quasielastic kinematics: x B = 1, q = 1 GeV/c, ω = GeV/c Determine momentum distributions: 0 < p miss < 500 MeV/c Determine Transverse-Longitudinal Asymmetry A TL : Impulse Approximation Limitation to 208 Pb(e,e’p) 207 Tl reaction Nikhef data at x B ~ 0.18

H. Hotchi et al., Phys. Rev. C 64 (2001) E Hall A Experiment Vs. KEK-E C(e,e’K) 12 B  12 C(  ,K + ) 12 C  Statistical significance of core excited states:

E Hall A Experiment Vs. FINUDA (at Da  ne) 12 C(e,e’K) 12 B  12 C(K - ,   ) 12 C  Statistical significance of core excited states:

E Hall A Experiment Vs. HallC E C(e,e’K) 12 B  Miyoshi et al., PRL 90 (2003) New analysis Statistical significance of core excited states:

E Hall A Experiment: status of 12 B  data 12 C(e,e’K) 12 B  Statistical significance of core excited states : Energy resolution is ~ 750 keV with not fully optimized optics for momenta reconstruction Work is in progress to further improve the resolution, hence the signal/noise ratio more checks and tuning have to be done, …but : the data are already of extremely good quality … to be published soon