JLab Spin Experiments Completed/on-going: n (3He), both g1 and g2, 0.02 GeV2 < Q2 < 5 GeV2 p/d, g1, 0.02 GeV2 < Q2 < 5 GeV2 p/d, g2, Q2=1.3 GeV, 2 GeV2 < Q2 < 5 GeV2 Spin experiments to be done at 6 GeV: g2p at low Q2 (not practical with 12 GeV) g1d, constraint on DG Semi-SANE, flavor decomposition Transverse spin @ CLAS with HD

Neutron Spin Polarizabilities: “dLT Puzzle” Significant disagreement between data and both ChPT calculations for dLTn g0n dLTn E94-010, PRL 93 (2004) 152301 Q2 Q2

Proton g2 at low Q2 Polarized Proton Target g2 : central to knowledge of Nucleon Structure but remains unmeasured at low Q2 Polarized Proton Target Septa Magnets for low Q2 Critical input to Hydrogen Hyperfine Calculations Violation of BC Sum Rule suggested at large Q2 State-of-Art PT calcs fail dramatically for LT n LT Spin Polarizability BC Sum Rule K. Slifer Crimea07

Polarized Targets Polarized 3He: good shape Polarized NH3/ND3 targets High polarization: 35% 65% Highest pol. lumi: 1036 Polarized NH3/ND3 targets Magnet, other hardware Performance, FOM Transverse polarization Polarized HD