Single-Spin Asymmetries in Inclusive and Exclusive Hadronic Processes

We investigate the single-spin asymmetries in inclusive and exclusive processes of electron-proton scattering and electron-positron annihilation. In the decomposition of hadronic tensor, a Lorentz symmetric spin-dependent term is generally present. The existence of such a term implies single-spin asymmetries in these processes and these single-spin asymmetries for baryons can be understood in a unified manner. We argue that it is important to measure the single-spin asymmetries in both inclusive and exclusive processes for the $\Lambda$ production at the present B-factories. This will lead to the first measurement of the structure function of the symmetric spin-dependent hadronic tensor in these processes.