Soft gluon effects in the extraction of higher twists at large Bjorken x

Existing data on the (unpolarised) transverse structure function of the pro ton are analyzed for large values of the Bjorken variable x. The leading-tw ist and a phenomenological higher-twist contributions are simultaneously de termined from a power correction analysis of the Nachtmann moments for valu es of the squared four-momentum transfer between similar to 1 and 20 (GeV/c )(2). The results obtained adopting the next-to-leading-order approximation and those including the effects of soft gluon resummation are compared. Th e sensitivity of the extraction of large-x higher twists to high-order radi ative corrections as well as to the value of alpha (s)(M-Z(2)) is illustrat ed. (C) 2000 Elsevier Science B.V. All rights reserved.