Simple mechanism of softening structure functions at low transverse momentum region

The relevance of non-abelian dipole configurations of quarks in forming nuc leus structure functions is discussed. It is shown that radiation generated by dipole configurations while moving relativistically along their axes is described by distributions which are finite and infrared stable in a low t ransverse momentum region. They approach exponentially the perturbative reg ime of large transverse momenta and the rate of this transition is defined by the distance between the dipole charges in its rest frame. (C) 1998 Else vier Science B.V. All rights reserved.