High-twist contribution to the longitudinal structure function FL at high x

We perform the NLO QCD fit to the combined deep inelastic scattering (DIS) data at high x from the SLAC, BCDMS, and NMC collaborations. The model-independent x shape of the high-twist contribution to structure function F-L is extracted. The twist-4 contribution to F-L is found to be in a qualitative agreement with the predictions of the infrared renormalon model. The twist-6 contribution exhibits a weak trend to negative values, although on the whole, it is compatible with zero within the errors.