Exclusive electroproduction of vector mesons and transversity distributions - art. no. 034023

We show that the leading twist contribution to exclusive electroproduction of transversely polarized vector mesons vanishes at all orders in perturbat ion theory. Therefore one cannot extract information on the quark transvers ity distribution of the nucleon from this reaction. In turn one has that th e produced vector meson is purely longitudinal in the large-Q(2) limit, whi ch provides a new test of the dominance of leading twist at finite Q(2). [S 0556-2821(99)04303-9].