Comparative Analysis of Transversities and Longitudinally Polarized Distributions of the Nucleon

We carry out a comparative analysis of the transversities and the longitudinally polarized parton distribution functions in light of the first empirical extraction of the transversity distributions recently done by Anselmino et al. It is shown that the precise determination of the isoscalar tensor charge, which is defined as the 1st moment of the isoscalar combination of the transversity distributions, is of fundamental importance for clarifying the internal spin structure function of the nucleon.