Applications of Symmetry Breaking in Determining PDFs of the Nucleon

Studying the possible breaking of various parton model symmetries by the parton distribution functions of the nucleon can provide important information for the non-perturbative structure of hadrons and the strong interaction. We review theoretical calculations for the breaking of flavor symmetry, quark-antiquark symmetry and charge symmetry in the unpolarized and polarized nucleons using the meson cloud model. We report an estimation for the total distribution of strange and antistrange quarks in the nucleon by combining theoretical calculations of SU(3) flavor symmetry breaking with light antiquark distributions obtained from global analysis of available experimental data.Comment: 8 pages, 4 figures, LaTeX, talk presented at Pacific Spin 2011 (June 20-24, 2011, Cairns, Australia), to appear in the conference proceedings (AIP

Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases

The chiral magnetic and chiral separation effects---quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma---have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled atomic gases are potential simulators of the chiral magnetic and separation effects.Comment: V2: 13 pages, 5 figures, discussions on Bose gases are cut out, published versio