Hard exclusive electroproduction of a pion in the backward region

Abstract

We study the scaling regime of pion electroproduction in the backward region, $eN\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{N}^{\ensuremath{'}}\ensuremath{\pi}$. We compute the leading-twist amplitude in the kinematical region, where it factorises into a short-distance matrix element and long-distance dominated nucleon distribution amplitudes and nucleon to pion transition distribution amplitudes. Using the chiral limit of the latter, we obtain a first estimate of the cross section, which may be experimentally studied at JLab or Hermes.