Time-reversal odd fragmentation and distribution functions in pp and ep single spin asymmetries

We present some estimates of T-odd fragmentation and distribution functions, $H_1^\perp$ and $f_{1T}^{\perp}$, evaluated on the basis of a fit on experimental data in p$^\uparrow$p. Assuming the T-odd fragmentation function to be responsible for the single spin asymmetry in pion production in p$^\uparrow$p, we find the ratio $H_1^{\perp}/D_1$ to be in good agreement with the experimental results from DELPHI data on Z -> 2$-jet decay. We use our estimates to make predictions for ep$^\uparrow$.