Nucleon Spin Flavor Decomposition through Semi-Inclusive DIS Measurements on a Polarized 3He target

Semi-Inclusive Deep-Inelastic Scattering reactions can provide quark flavor tagging through the detection of the leading-hadron. Precise measurements of double-spin asymmetry $A_{1N}^h$ ($h=\pi^+, \pi^-, K^+, K^-$) can provide strong constrains on valence quark polarization, as well as sea quark polarization, and to access the possible polarized sea flavor asymmetry $\Delta \bar{u} - \Delta \bar{d}$. We emphasize that there are three independent methods to access polarized sea flavor asymmetry: 1. Next-Leading-Order QCD global fit method, as in DSSV2008, LSS2010 etc., 2. Leading-Order ``purity method,'' as used by HERMES and COMPASS experiments, 3. Leading-Order ``Christova-Leader'' method in which helicity asymmetry of the yield difference $\pi^+ - \pi^-$ is used to extract valence quark polarization $\Delta u_v$ and $\Delta d_v$, and polarized sea flavor asymmetry can be extracted when combining with inclusive spin structure $g_{1p}$ and $g_{1n}$. Taking a JLab-12GeV SIDIS experiment (PR12-14-008) as an example we show the sensitivity to polarized parton distributions and the polarized sea's flavor asymmetry.