Parton-hadron duality in unpolarized and polarized structure functions

We study the phenomenon of parton-hadron duality in both polarized and unpolarized electron proton scattering using the HERMES and the Jefferson Lab data, respectively. In both cases we extend a systematic perturbative QCD based analysis to the integrals of the structure functions in the resonance region. After subtracting target mass corrections and large x resummation effects, we extract the remaining power corrections up to order 1/Q(2). We find a sizable suppression of these terms with respect to analyses using deep inelastic scattering data. The suppression appears consistently in both polarized and unpolarized data, except for the low Q(2) polarized data, where a large negative higher twist contribution remains. A similar trend is found by using phenomenological parametrizations of the data, which include nonperturbative type corrections. Possible scenarios generating this behavior are discussed.