Deeply inelastic pions in the exclusive reaction p(e,e'π+)n above the resonance region

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A model for the p(e,e'π+)n reaction which combines an improved treatment of gauge invariant meson--exchange currents and hard deep--inelastic scattering (DIS) of virtual photons off nucleons is proposed. It is shown that DIS dominates and explains the transverse response at moderate and high photon virtualities Q² whereas the longitudinal response is dominated by hadronic degrees of freedom and the pion electromagnetic form factor. This leads to a combined description of the longitudinal and transverse components of the cross section in a wide range of photon virtuality Q² and momentum transfer to the target t and solves the longstanding problem of the observed large transverse cross sections. The latter are shown to be sensitive to the intrinsic transverse momentum distribution of partons.