Power corrections to the structure functions of proton and deuteron

Power corrections to the Q(2) behaviour of the low-order moments of both th e longitudinal and transverse structure functions of proton and deuteron ha ve been investigated using available phenomenological fits of existing data in the Q(2) range between 1 and 20 (GeV/c)(2). The contributions of (targe t-dependent) multiparton correlations to both 1/Q(2) and 1/Q(4) power terms have been determined in the transverse channel, while the longitudinal dat a appear to be consistent with a pure (target-independent) renormalon pictu re. Finally, the extracted twist-2 contribution is found to be compatible w ith the hypothesis of an enhanced d-quark parton distribution at large x (x greater than or similar to 0.7).