Singular gauge fields in inclusive and differential cross sections

We study differential and inclusive cross sections for the creation of massless fermions in the presence of a static external non-Abelian field Acl. We calculate to all orders in Acl the correction to the quantum cross section which is suppressed by one power of the energy. Corrections of this type are found to be important even at high energy for sufficiently exclusive cross sections if the classical field has singularities along a line. Their contribution to inclusive cross sections, on the other hand, remains small at high energies.