  We investigate the correlation of di-hadron productions between the current
fragmentation region (CFR) and target fragmentation region (TFR) in deep
inelastic scattering as a probe of the nucleon tomography. The QCD
factorization and powering counting method are applied to compute the relevant
diffractive parton distribution functions in the valence region. In particular,
we show that the final state interaction effects lead to a nonzero longitudinal
polarized quark distribution associated with the unpolarized nucleon target.
This explains the observed beam single spin asymmetry (BSA) from a recent
Jefferson Lab experiment. We further show that the BSA in the single
diffractive hadron productions in the TFR, although kinematically suppressed,
also exists because of the final state interaction effects.
