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[PAST EVENT] Physics Seminar
November 19, 2015
3:30pm - 4:30pm
Abstract:
Our understanding of the nucleon spin structure is still far from complete. Although we know a lot about the quark momentum and helicity distributions in the nucleon, we are just beginning to understand the quark transverse spin distributions. Quark transverse-spin and transverse-momentum effects in the nucleon are observed in a variety of processes in the high-energy e-p and p-p collisions. Semi-inclusive Deep Inelastic Scattering (SIDIS) process is one of the powerful ways to measure these effects in electron scattering experiments. In particular, the single and double spin asymmetries (SSA/DSA) obtained from SIDIS reaction on a polarized nucleon target are sensitive to transverse-momentum dependent parton distribution functions (TMDs). I will present some recent results of SSA and DSA from the JLab Hall-A transversity experiment which measured these asymmetries in the valence-x region for charged hadrons using a polarized helium-3 target. I will also discuss plans for the future precision experiments at JLab using polarized proton and helium-3 targets and the proposed Solenoidal Large Intensity Device (SoLID) in Hall-A. These experiments will cover a wide range of kinematics in all four dimensions (x,Q^2,p_T,z), which is very crucial for extracting TMDs and to provide a 3D image of nucleon in momentum space.
Our understanding of the nucleon spin structure is still far from complete. Although we know a lot about the quark momentum and helicity distributions in the nucleon, we are just beginning to understand the quark transverse spin distributions. Quark transverse-spin and transverse-momentum effects in the nucleon are observed in a variety of processes in the high-energy e-p and p-p collisions. Semi-inclusive Deep Inelastic Scattering (SIDIS) process is one of the powerful ways to measure these effects in electron scattering experiments. In particular, the single and double spin asymmetries (SSA/DSA) obtained from SIDIS reaction on a polarized nucleon target are sensitive to transverse-momentum dependent parton distribution functions (TMDs). I will present some recent results of SSA and DSA from the JLab Hall-A transversity experiment which measured these asymmetries in the valence-x region for charged hadrons using a polarized helium-3 target. I will also discuss plans for the future precision experiments at JLab using polarized proton and helium-3 targets and the proposed Solenoidal Large Intensity Device (SoLID) in Hall-A. These experiments will cover a wide range of kinematics in all four dimensions (x,Q^2,p_T,z), which is very crucial for extracting TMDs and to provide a 3D image of nucleon in momentum space.